IEEE ICEE encourages submissions in all areas of Electron, Phonon and Spin Devices including MEMs /NEMs, however, with special emphasis on following areas:
IEEE ICEE encourages submissions in all areas of Electron, Phonon and Spin Devices including MEMs /NEMs, however, with special emphasis on following areas:
Papers are solicited in the area of wide band gap (WBG) semiconductor devices. While relevant work pertaining to all areas of materials, devices and systems based on WBG such as SiC, III-nitrides, diamond and Ga2O3 & its alloys are welcome, the focus of this thematic session will be on III-nitrides vs. the emerging family of Ga2O3 devices. Particular emphasis would be laid on all aspects of power device technology including materials growth vis-à-vis the promises and challenges associated with III-nitride and Ga2O3 power transistors. Submissions related to advances on various aspects of III-nitride RF devices, GaN RF HEMTs for 5G, reliability of GaN-based power/RF devices especially on silicon substrates, UV devices including detectors and LEDs, the commercial relevance and promises of WBG devices for systems etc. are highly encouraged. The talks will be aimed at fostering and enabling discussions such as “Will Ga2O3 rival GaN for power electronics?”, “Are WBG devices relevant at all if Silicon performs so well?”, “Do WBG devices for UV emission and detection have any market potential?”, “Will GaN RF lose out to Silicon in the area of 5G?” etc.
Papers are solicited on novel photovoltaic and other energy harvesting devices. Interesting work in any material system and device is most welcome. However, the focus of this symposium will be on Si and perovskite PV. Topical areas include novel Si PV concepts, commercial Si PV, techno-economic analysis, advances on efficiency, manufacturability, scalability, stability and toxicity of perovskite solar cells. The session will try to enable topical discussions, e.g. “Will perovskite PV every be commercialised?”; “What makes lead halide perovskite so special?”; “In light of Si PV’s sucess, is there any point of research on photovoltaics?”; and “What is the best way for academics to contribute to solar research in India”. Papers and talk that further such a discussion are more welcome.
The scope of the photonics meeting is to bring researchers in the area of guided wave photonics; integrated and fiber, and lasers to share their finding with a broader audiences. We solicit papers that report progress in all branches of integrated photonics, silicon photonics, linear/nonlinear photonics, lasers and optical communication. The paper is expected to present innovative solutions, new device and system concepts or demonstrations. The conference aims to provide a global overview of the current status in this fast-evolving field and a platform for exchange of ideas.
Silicon photonic devices and circuits for communication and sensing applications, wavelength selective devices, light manipulation using guided wave systems, integrated quantum optics, on-chip sensing of bio-photonics, photonic crystal basics and applications, integrated circuit enabled systems, surface plasmon waveguides and devices, on-chip optical cavity for linear and non-linear applications, novel materials for integrated photonics, opto-fludics, theory and modelling, light-matter interaction at nano-scale, integrated photonics based on III-V, II-VI and group IV materials, photonics enabled RF-over-fiber system, light modulators, photodetectors, and integration and active and passive devices.
All aspects of nonlinear photonics and applications. This includes nonlinear optical phenomena in various media such as crystals, fibers and integrated waveguides. On laser sources and systems including high power fiber lasers, solid-state lasers and associated frequency conversion techniques. Materials and devices associated with these systems Components, systems and demonstrations in optical communications in guided and unguided configurations. Ultrafast photonics and phenomena
Traditional group IV devices are still the workhorse of the industry. However scaling requires innovations like fins, nanowires and nanosheets as well as materials engineering from Si, Ge to strain, gate dielectric and contacts. Papers are solicited on experiments and analysis of novel physics and applications of traditional group IV (Si,Ge) transistors.
Non-volatile charge, spin, thermal and ion based memories like Flash, Ferro-electric RAM, Phase Change Memory (PCM), Magneto Resistive RAM (MRAM/STT-MRAM) and Resistance RAM (RRAM) are the new memories to bridge the gap between magnetic hard disk and cache. Paper are solicited on experiments, modeling and analysis of materials and devices of such memories to enhance their performance in a system and emerging applications of these memory devices.
Growing volumes of data demand new and unconventional information processing techniques fundamentally different from traditional Von-Neumann computing. Some of these include low-power emerging circuits/devices implementing algorithms based on machine-learning and neuromorphic computing principles. Topics of interest include circuits and devices related to spiking, non-spiking neuromorphic, ML, AI computing and applications.
Technologies that exploit the quantum properties, such as superposition and entanglement, and explicitly address individual quantum states are referred to as quantum technologies (QT). Global companies, including Google, IBM, Intel, Microsoft and Toshiba have recently started to invest heavily in QT to build functional quantum computers and sensors for the masses. The competing technologies include superconducting qubits, trapped ions, electrons on helium, quantum dots, solid state color centers, cold atoms, nuclear magnetic resonance (NMR), discrete-variable photonic (LOQC), continuous variable photonic including other novel approaches such as quantum annealing, Ising machines, adiabatic quantum computing using superconducting or ion arrays, etc. Keeping this revolution in mind, the central theme of this track of the ICEE conference is to compare and contrast various approaches against key metrics such as (1) scalability of platform (2) qubit coherence time (3) ease of qubit control (4) targeted gate fidelity as needed to translate the proof of principal concepts to technologies for the future.
Spintronics or magneto-electronics is an area of active research because of the tremendous potential ahead both in terms of fundamental science and technology. Here, one exploits the spin degree of freedom of the electrons along with its charge. So, Spintronics combines standard microelectronics with spin-dependent effects. Hence, one can expect a new generation of devices with completely different functionality. The advantages of some of the Spintronics devices would be non-volatility, increased data processing speed, decreased electric power consumption, and increased integration densities compared to semiconductor devices. In this conference, we will be discussing and brainstorming about different present and futuristic aspects of science and technology in this area which include magnetic memories, spin torque effects, spin-orbit torque, spin waves, magnetization dynamics, magnetic imaging, skyrmions, spin torque oscillators and diverse theoretical tools.
The emergence of graphene as the thinnest electrical conductor with exceptional carrier mobility has triggered a new genre of electronic devices. The discovery of graphene was later followed by stabilization of monolayers of transition metal dichalcogenides, such as MoS2, WSe2, MoSe2 etc, all of which show semiconducting, metallic or even superconducting properties that have been utilized in novel electronic architectures. The ultra-thin nature of the chalcogenide monolayers may overcome several bottlenecks of silicon electronics, such as the drain-induced barrier lowering or short-channel effects, while driving the miniaturization of electronic channels to atomic limit. The semiconducting nature of transition metal dichalcogenide molecular layers have led to functional electronic designs, particularly in the context of sensitizing electronic designs to optical radiation. The van Hove singularities in the density-of-states allows these materials to exhibit outstanding absorption coefficient even when the thickness is reduced to individual molecular layers. An on-chip integration of optical and electronic functionalities is a unique feature of 2D optoelectronics that has captured global fundamental and applied interest in this topic. Beyond high electrical mobility, new devices of tunnel field-effect transistors, or topological FETs are also being developed. One of the key developments in realizing 2D conduction channels for electronic and optoelectronic applications is the synthesis of van der Waals heterostructures by various means from the scotch tape method to chemical vapor deposition. We invite papers from researchers involved in synthesis, device physics and engineering of 2D materials to enrich the discussions on current status and the foreseeable future.
Papers are solicited in the areas of materials, devices and device modelling for printable, polymer substrate compatible, flexible, stretchable and conformable electronics and their components. The focus is expected to be on biomedical applications, FET’s and logic electronics, light emitting diodes, photovoltaics, RFIDs, shielding, wearable devices and sensors.
The objective of this track of the ICEE conference is to provide an international technical forum to showcase recent advances in micro/nano mechanical systems and microfluidics. Contributions describing the latest scientific research are solicited in the area of microelectromechanical system, nanoelectromechanical systems, nonlinear effects in mechanical systems, cavity optomechanics, opto-electro-mechanical system, optical M/NEMS sensors, M/NEMS based sensors, actuators and systems, biomechanics, bio-MEMS, mechanobiology, micro/nano fluidics devices, microdroplet generation and manipulations, control and transport of microdroplets and flow cytometry.
Analytical, numerical, and statistical approaches to modeling and simulation of electronic, optical, hybrid devices; physical and compact models for devices and interconnects, modeling of fabrication processes and equipment, material modeling, parameter extraction, early compact models for conventional, advanced technologies and novel devices, performance evaluation, design for manufacturing, reliability, variability, and technology benchmarking methodologies; mechanical or electro-thermal modeling and simulation; modeling of interactions between process, device, circuit, and packaging technology.
Papers are solicited in the areas of THz Sources, Detectors and Receivers, Frequency and Time Domain THz Devices, Components THz Materials, Spectroscopy, Instrumentation THz for applications in security and defense, biomedical imaging and astronomy and atmospheric sciences.
Max Zenghui Wang is currently a professor in the Institute of Frontier and Fundamental Sciences (IFFS) at the University of Electronic Science and Technology of China (UESTC) and a visiting professor in the Electrical Engineering and Computer Science Department (EECS) at Case Western Reserve University (CWRU), where he had worked as a Research Associate (2012-2014) and Senior Research Associate and Investigator (2014-2016). His research interests and expertise primarily focus on nanoscale devices and systems, particularly Nanoscale Resonators, and High-Frequency Resonant Sensors & Transducers. Prior to joining Case, during 2010-2012, he worked at Cornell University as a postdoc researcher. He earned a Ph.D. degree (2010) from University of Washington, Seattle, for building an ultra-high frequency NEMS resonant sensor with an individual single-walled carbon nanotube, and using it to detect and study the low-dimensional phase transitions of the atomic layer adsorbed on the nanotube surface. He is an expert on studies of emerging nanoscale devices and sensors based on new materials such as carbon nanotubes, graphene, and other low-dimensional nanomaterials, and has published 20+ research articles in peer-reviewed journals, including Science, Nature Nanotechnology, Nature Communications, Science Advances, Nano Letters, ACS Nano, Physical Review Letters, 2D Materials, etc.,. He has given dozens of invited talks and seminars at peer-reviewed conferences and research universities. He is an Associate Editor for Micro and Nano Letters, and has been serving on the Technical Program Committees for IEEE IFCS, IEEE Nano, and the MEMS/NEMS Technical Group at the American Vacuum Society (AVS) International Symposium and Exhibition
After completing MTech. in Nanotechnology from Amity University, Anshul Sharma worked on graphene at IIT Bombay. He joined Log 9 Materials in 2016 and since then is involved in doing research on graphene and developing technologies and commercial products based on graphene.
Rohan M Ganapathy (26), is a Director, CEO & CTO at Bellatrix Aerospace Pvt. Ltd. Bellatrix is an IISc incubated company involved in the development of advanced in-space propulsion systems. He is an Aeronautical Engineer with expertise in Spacecraft propulsion, Rocket propulsion and systems engineering. Bellatrix Aerospace received Technology Development Board’s National Award 2017 from the Hon’ble President of India Shri. Pranab Mukherjee for ‘Development of Technology with Potential for Commercialisation’. Rohan was also part of ‘Champions of Change’, a policy think tank of 100 company CEOs in the country organized by NITI Ayog and presided over by the Hon’ble PM Shri. Narendra Modi, where Rohan contributed in policy for ‘Research in Higher Education’. He was featured on Forbes India and Forbes Asia’s “30 under 30” lists in 2018. Bellatrix was also recognized among top 100 startups in Karnataka through Elevate 100 program and the company also received ‘Best Space Technology Company’ award 2018 from Government of Andhra Pradesh and “Promising Space Technology Startup2018” award from IESA.
Bio: Presently working as Vice President, Engineering in Astrome Technologies Private Ltd , a Space startup building the next generation technologies to provide affordable Internet from Space. He was the Founder & CEO of Cooltok which was in the field of telecom VAS product development. He led the product development and business strategy. Cooltok was acquired by Kirusa Inc, USA , in 2014. He was Founder & CEO of Wiwanet Solutions Pvt Ltd, a company that is a pioneer in providing Long Range Communication services for Fishermen inside sea. He was Senior Manager , leading theWiFi System Design Team in Broadcom . Led Several WLAN, WLAN-BT combo chip design teams in Broadcom spanning over SISO, MIMO and ensured successful high volume deployment of these devices in Worlds Top mobile companies like Nokia, Apple, Samsung, etc and retail customers like DELL, HP etc. He worked as System Design Architect in Athena Semi Conductors , which developed the first generation of WiFi chipsets with R&D centres in Bangalore, Greece and USA. Athena was Acquired by Broadcom Corp , USA, in 2005. Holds Several patents in Wireless PHY design arena and also Holds a B.E degree from NIT, Nagpur, INDIA.
Abstract: They will talk about Log 9 and its technology.
Abstract: Satellites need in-space propulsion systems for orbit raising and station-keeping applications. The satellite industry is undergoing a major transition from traditional chemical propulsion systems to efficient electric propulsion systems. Electric propulsion offers a host of advantages such as 10X higher specific impulse, increased payload capacity, increased satellite life and reduction in launch costs. Solid State Power Amplifier are replacing bulky analog vacuum tubes in the areas of communication as well as propulsion. This talk will focus on how SSPAs are augmenting the capabilities of electric propulsion systems.
Abstract: Internet connectivity is still a dream for billions of people living in rural and semi-urban areas of the developing countries. Providing internet to them requires a different approach as the traditional modes like laying optical fiber are not economically viable. To address this, we are developing next generation satellite communication technologies that significantly reduce the cost of delivering internet to semi-urban and rural areas.
Skin is an amazing organ that not only performs a variety of functions, but also is preferred route for drug delivery. Hollow microneedle (MN) arrays offer versatility and control to transdermal (skin based) drug delivery systems where a variety of drugs and their continuous supply are concerned. They may be used as a standalone device or be integrated with the drug reservoir or micropump. By adopting innovative approach to learn from nature, we looked at ideal solutions that inspire transdermal drug delivery devices. The traits that nature has imbibed in mosquito for its survival become a plethora of information for us. The female mosquito sucks blood through its proboscis by using two forms of motion of pressing down the labium and applying vibration. The design and idea can be well applied to reduce force required for microneedle insertion and enhancing precision in penetration depth. An important aspect in this regard is the effective fluidic communication between the reservoir and the MNs on a robust substrate. In a novel attempt of its kind, we present the development hollow SU-8 MNs on a pre-etched silicon wafer having through holes. SU-8 MNs are fabricated by direct laser writing by aligning them on the silicon substrate with microfluidic ports pre-etched by wet chemical etching. Each process step was optimized after a parametric study. The optimized MNs (500–600 µm length, 100 µm outer diameter and 40 µm inner diameter) have an aspect ratio of 5. The MNs have been characterized for mechanical strength and biological insertion tests for their effectiveness in puncturing the skin without breaking. The maximum compressive force and bending forces for the MNs are 0.27 N and 0.022 N per needle, which are higher than the resistive skin penetrating forces. The microfluidic characterizations show the development of hollow MN lumen with a flowrate of around 0.017 µl s−1 at 2 KPa pressure difference at the inlet. The array of 10 × 10 MNs with 500 µm spacing was able to successfully penetrate mice and rat skin without any breakage. Further, the SU-8 polymer films can be turned into a fracture-resistant, glassy form of carbon that holds immense promise for drug delivery. Heat treatments in an oxygen-free oven sharpened the microstructures into microneedles composed almost exclusively of randomly ordered carbon atoms. Characterizations revealed the glassy carbon structure could exert forces strong enough to pierce human skin with minimal risk of breakage.
Thin film electronics on flexible substrates offer interesting possibilities to change the way we interact with the environment. They promise novel manufacturing techniques such as printed electronics, roll-to-roll fabrication; applications such as wearable electronics for health diagnostics; flexible sensors and actuator arrays such as displays and image sensors etc. However, these advantages are followed by a host of reliability issues in devices and interconnect.
Interconnects on flex experience open circuit fault during operation due to mechanical flexing, differential thermal expansion, electro static discharge, electro migration and environmental degradation. To improve the reliability of the interconnect to open failures several passive approaches such as stretchable conductive materials, meandered and helical geometries, the use of spongy substrates etc have been investigated. These approaches however are passive and only improve the reliability of the interconnect to mechanical causes of failures.
We describe an active approach where in open faults in interconnects are automatically detected and repaired in real time during operation. The self healing mechanism is achieved using a dispersion of conductive particles in an insulating fluid that is packaged over the interconnect. Upon the occurrence of a fault in a current carrying interconnect, the field developed across the gap polarizes the particles in the dispersion. The polarized particles then experience dipole-dipole attractive forces and form a bridge across the gap thereby healing the fault.
In this talk, we present the physics and results pertaining to the stability of the heal, the time taken to heal and the stretchability of the heal. We demonstrate highly stretchable heals with strains from 12 to 60 depending on the strain rate and with a conductivity of 5×105 S/m.
Sanjiv Sambandan obtained his BTech in Electrical Engineering (Energy Systems) from the Indian Institute of Technology, Kharagpur, India in 2002 and PhD in Electrical and Computer Engineering from the University of Waterloo, Canada in 2006. From 2006-2010 he was with the Electronic Materials and Device Lab, Xerox Palo Alto Research Centre, California, USA. He is jointly appointed as a faculty at the Indian Institute of Science, Bangalore, India and the University of Cambridge, Cambridge, UK. He is also the founder and director of openwater.in, a clean water start up.
The prospect of sheets or rolls of circuitry fabricated on ultra-thin, extremely durable substrates pliable enough to be shaped into flexible configurations is nothing short of revolutionary. Such a breakthrough could enable amazing new capabilities and products – from rollable displays combining the functions of TVs and computing, to stretchable wearable products and ultra-thin mobile devices. Applied Materials is at the forefront of providing OLED display and flexible roll-to-roll (R2R) manufacturing solutions that can help enable technology innovations for creating new generations of more lightweight, flexible form factor products. In this talk, Dr Suraj Rengarajan will focus on process technologies that are critical to moving flexible displays from a vision to a reality. The presentation covers R2R processing inflections for the display and IoT industries and explores how creating flexible form factors for next-generation consumer electronic devices requires the use of polymeric films. Most of these polymeric materials are manufactured in the form of a roll, resulting in the increased utilization of R2R processing. He will also discuss how Applied is developing R2R technologies for next-generation, large-area flexible electronics applications.
S. Sundar Kumar Iyer is a faculty member in the Department of Electrical Engineering at IIT Kanpur. His main area of research interest is organic solar cells. At the National Centre for Flexible Electronics, he and the FlexPV team are involved in building solar cells and modules on flexible substrates that can be used for practical electronic systems.
The inclusion of photovoltaic (PV) cells on flexible substrates for flexible electronic systems could allow building more sophisticated systems with improved capabilities. There is also the potential for commercial applications of stand-alone PV systems implemented on flexible substrates. Some of the advantages for flexible PV modules are light weight, devices conformal to surfaces and ease of storage, transport and deployment.
In this presentation, the gamut of PV technologies that can be made flexible or implemented on flexible substrates will be highlighted. Following this, the implementation of organic solar cells on flexible substrates at IIT Kanpur will briefly discussed. The possibility of using ternary hybrid hetero-junction structures to improve device efficiency by modifying an existing bulk-heterojunction process line will be presented with an example.
Educational Qualification :
Award/Prize/Certificate etc. Won :
While resonant cantilevers as biological sensors are well established with cantilevers of micron/submicron dimensions demonstrating sub-femtogram mass sensitivity in the detection of cells, DNA, viruses, and other biomolecules, most of these are in air or vacuum environment. Many biological processes occur in liquid ambience and the operation of the same cantilevers in aqueous environment poses a problem due to viscous damping suppressing the cantilevers quality factor (Q) and reducing the sensitivity. Another problem with bio-sensing in aqueous environment relates to the repeatability and reliability in results obtained. The minimum limit of detection depends on Q and the mass of the cantilever sensor and, as the signal to noise ratio in liquid medium is low, the dependence of this limit on the external factors increases
We follow a three pronged approach towards achieving better sensitivity and reliability for cantilever based sensors in liquid medium. Using silicon and polysilicon cantilevers, we first improve the measurement and the data analysis techniques. For measurements, we have used the frequency sweep (FS) method with a Laser Doppler Vibrometer, and FS and the Phase Locked Loop (PLL) methods with the Cantisens unit. Two data analysis protocols have been explored for improving the error margins. Secondly, the functionalisation (immobilisation) techniques have been optimised for the maximum attachment of the bioanalyte to the cantilever beam surface. Thirdly, we have used smaller cantilevers and higher resonant modes to reduce the effect of damping and improve the mass sensitivity. All these techniques have been used to investigate a few different systems like: antibody/antigen; live/dead e-coli; triglycerides; urea; and some standard biomarkers for pathogens.
Micromechanical resonators play a pivotal role in MEMS sensor and actuator industry akin to the role of transistors in IC industry. One of the key performance characteristics of a micromechanical resonators is quality factor, a measure of energy loss in the resonator. In micromechanical resonators, the principal energy loss mechanisms are air damping, thermoelastic dissipation, anchor/clamping loss, resistive loss and Akhieser effect. A resonator must be suspended from a supporting anchor structure. Anchor loss quantifies the energy lost from the resonator to the anchor.
Anchor loss has been modelled analytically using a phonon-based framework as well as acoustic source-based framework. Both these modelling techniques make the underlying assumption that energy that is radiated out of the boundary between the resonator and the anchor never returns. A COMSOL based method explicitly applies this concept using perfectly matched layers (PML) which consists of many tunable parameters. Considerable literature exists that show their data matches that of COMSOL simulation. However, until recently, it was very difficult to fabricate a device that was only limited by anchor loss. Most of the data relies on accurate modeling of other energy losses to back out the expected clamping loss.
In this talk, we will look at the current state of modeling of anchor loss in micromechanical resonators. We will look at some of the evidence presented in literature which substantiate these models. Finally, we will introduce a method for studying anchor loss in an isolated fashion and look at some surprising results that completely negate the results of current models, thereby conveying future scope of research in this area.
Dr. Saurabh Arun Chandorkar obtained his BTech in Mechanical Engineering from IIT Bombay in 2003. He received his M.S. and Ph.D. in Mechanical Engineering with a minor in Electrical Engineering from Stanford University in 2009. He worked as a postdoctoral fellow in the area of adaptive Nanoimprint lithography in the Electrical Engineering Department of Stanford University from 2009 to 2010. He worked in Intel Mask Production facility in an R&D group for 6 years where his efforts were directed toward providing complete turn-key solutions for newly emergent issues in mask technologies for 1276(11nm) and 1278 (7nm) nodes. He was awarded two Intel Logic Technology Development (LTD) Divisional awards. In 2017, he worked in Stanford University as a lecturer. He joined IISc Bangalore as an Assistant Professor in December 2017 where he conducts research on MEMS/NEMS with special interest in resonators, packaging solutions and advanced system development.
There are well established limits in passive imaging in terms of resolving two-point sources, such as the Rayleigh limit or the optical space-bandwidth product. However, from a statistical inference perspective these limits do not account for the inherent uncertainty that accompanies optical measurements, e.g. detection noise. Classical information theoretic analysis of two-point sources separation problem shows that it is indeed possible to infer the source separation below the so-called Rayleigh limit, albeit with rapidly decreasing precision. While this result is known, it has only been recent discovered that it is indeed possible to achieve better inference precision, say for the two-point source problem with alternate optical measurements, which indeed achieves the ultimate quantum information theoretic limit. As such analyzing the quantum information theoretic limit of various passive imaging problems, for classical optical sources/illumination, and subsequently designing unconventional optical measurements that achieve these fundamental limits has garnered a lot of interest in the imaging and sensing community. I will present some recent results, that my group and collaborators have uncovered, regarding quantum information theoretic limit for two-point source and line source passive imaging problems. Our analysis quantifies the improvement achievable with alternate optical measurements relative to traditional focal plane array measurements, for various operational scenarios relevant to realworld implementation. We demonstrate that quantum information theory inspired optical measurement designs can achieve substantial performance improvements over the traditional imaging system design, even in the presence of a nonideal optical implementation and other system uncertainties.
Dr. Amit Ashok is an Associate Professor in the College of Optical Sciences and the Department of Electrical and Computer Engineering at the University of Arizona. He received his Ph.D. and M.S. degrees in Electrical and Computer Engineering from the University of Arizona and the University of Cape Town respectively. Before joining the University of Arizona as a faculty, he was a senior research scientist in the R&D division of OmniVision Technologies, where he worked on novel computational imaging system designs for commercial applications ranging from security to mobile phone cameras. Dr. Ashok’s research interests include computational/compressive imaging and sensing, Bayesian inference, statistical optics, and information theory. He has made several key contributions in taskbased joint-design framework for computational imaging and information-theoretic system performance measures across several imaging modalities spanning RF to visible/IR and X-ray domains. He has over 50 peer-reviewed publications, holds several patents, and has been invited to speak at OSA, IEEE, SIAM, SPIE and Gordon research conferences. He currently serves as a topical editor for OSA’s JOSA A journal and a general chair of SPIE’s Computational Imaging and Anomaly Detection and Imaging with X-ray conferences.
Chipscale cavity opto-mechanics studies the interaction of photons and phonons in micro-resonators that simultaneously host high quality factor mechanical and optical resonances with strong spatial overlap. In this talk, I will discuss a case study of an integrated silicon opto-mechanical system, and highlight the various experimental capabilities that can be realized. One of the novel applications enabled by such a system is direct conversion of intensity modulation of near-IR laser light to motional electric current wherein the device acts as a photon-phonon translator. I will also demonstrate the unique ability of such a system to use the back-action of the optical field to launch self-sustained oscillations of the mechanical mode with zero flicker noise, which can be used as a stable timing reference as a resonant sensor, and as a low noise parametric amplifier, as well as multi-GHz mechanical oscillations. Towards the end of the talk, I will briefly highlight achievements from other groups in this field, and present my thoughts on future directions in this area.
Education:
Experience:
Ab initio simulations have found applications in a wide range of industries from aerospace to pharmaceuticals. Within the semiconductor industry, ab initio simulations are regularly used to engineer (i) either the right material system (e.g. contacts, channel material, films in high-k metal gate stacks) and/or (ii) identify the appropriate process conditions (e.g. anneals, material incorporation, etc.) for fabricating devices with desirable characteristics. Despite the well-known band-gap underestimation issue, ab initio simulations could be effectively used to understand and optimize certain process techniques in effective work function (EWF) engineering. In this presentation, I will talk about the role played by ab initio simulations in providing a fundamental understanding of certain process techniques used for EWF engineering. The role of ab initio simulations in EWF engineering will be illustrated using the following examples: (i) impact of intermediate barrier film thickness, (ii) impact of oxygen incorporation in the metal gate and (iii) the role played by dipole layers. I will also discuss the challenges involved in applying ab initio simulations to these problems and some corrective techniques.
Education:
Experience:
Shri Hari Babu Srivastava, Outstanding Scientist and Director of Laser Science and Technology Centre (LASTEC), Delhi, is currently spearheading various technology and product development initiatives in the areas of high power lasers, laser spectroscopy and laser countermeasure applications. Prior to this, he has also worked in the areas of line of sight stabilization and electro-optical fire control and surveillance systems, leading multi-disciplinary teams towards development of equipment for Indian Armed Forces.
He is an alumnus of IIT Roorkee and IIT Kanpur from where he obtained his B.E. and M.Tech. degrees in Electrical Engineering, respectively. He is author/co-author of around 30 research papers, numerous DRDO reports and four technical books/chapters in English and Hindi. He is a recipient of DRDO Cash and Group Technology Awards for his contribution towards various DRDO programmes.
Silicon photonics has been considered to be one of the few enabling technologies for the 21st century. It is finding many novel applications in the area of high speed optical interconnects in semiconductor IC technology, lab-on-chip sensing, and futuristic quantum optic computation and secured communication systems. The silicon photonics technology triumph has been possible because of the advancement of silicon CMOS technology nodes along with a little add-on for the co-integration of electronics and photonics devices. Low-loss photonic wire waveguide in silicon-on-insulator (SOI) platform with tightly confined guided mode has been in the forefront in designing the basic building blocks like directional coupler, microring resonator and Mach-Zehnder interferometer, etc. used for large-scale integrated silicon photonics circuits. By leveraging the large thermo-optic coefficient of silicon (1.86 × 10-4 K-1), various waveguide thermo-optic phase shifter designs have been explored in recent times for the on-chip active control of integrated optical components. microheaters In this talk, I’ll discuss first about various design approaches for thermo-optic phase-shifters, related state-of-the-art-technology, their overall performance analysis. Thereafter, I will be presenting some thermo-optically reconfigurable silicon photonics devices/circuits recently demonstrated at IIT Madras.
Demand for data infrastructure spurred by the explosion in big data and artificial intelligence is forcing us to reexamine the basic semiconductor components needed to build the infrastructure. Magnetic and solid state storage as well as memory components that dominate this market today will face extreme pressure to continue scaling. No single device will meet the often conflicting demands for cost, density, speed, latency, and power for application specific architectures . This talk will examine the current state of the art in data storage components and the needs going forward.
Bijoy Krishna Das obtained his master degree in solid state physics from Vidyasagar University, Midnapore, India (in 1996) and PhD degree (Dr.rer.nat) in integrated optics from University of Paderborn, Germany (in April 2003). Prior to his PhD research in Germany, Dr. Das started his research career in the area of integrated optics at the Microelectronics Centre, IIT Kharagpur for three years (January 1996 – December 1998). His postdoctoral research carried out in three different countries First, he was an FRC Postdoctoral Fellow in the Graduate School of Engineering, Osaka University, Osaka, Japan (2004-2005). Later, he joined as a postdoctoral researcher in the Center for Optical Technologies, Lehigh University, Bethlehem, PA, USA. In April 2005, he rejoined the Integrated Optics Group in University of Paderborn as Wissenschaftlicher Mitarbeiter and continued his research on integrated nonlinear optical devices. He also worked for a while at Laboratoire Aime Cotton, CNRS, Orsay, France. Since August 2006, Dr. Das has been associated with the Dept. of Electrical Engineering, IIT Madras, where he is currently holding a full Professor position. He has published more than 75 research articles in peer reviewed journals and conference proceedings. His present research focus is silicon photonics devices and circuits for optical interconnect and quantum optic application; integrated RF photonics signal processing; and lab-on-chip biomedical applications.
Dr Nalamasu provides an overview of the Global Technology Inflections which are shaping the future today, and promise to have an huge impact of how we will live tomorrow. One common thread through all these inflections which range from Energy, Information, Transportation, Manufacturing and Health, is Materials Engineering. Innovations in materials that drove Moore’s Law and made electronics ubiquitous, have the power to make a similar impact in other industries too. In his talk Dr Nalamasu goes over Materials Engineering enabled scaling and the impact it has had on the semiconductor Industry. The era of AI and Big data promises to be an even bigger computing wave, which will require significant enhancements in performance, both for the processor as well as memory storage, necessitating new energy efficient compute architectures and materials. As the consumption of information becomes more visual, drastic performance improvements are required in electronics, displays, storage and optics. Materials engineering innovations have the ability to provide sustainable and scalable solutions to many of these challenges. Another huge transformations that we are beginning to see is in the area of transportation, where the conventional models are bring disrupted by shared economy, autonomy and the electrification of transport. India promises to play a lead role in driving this change. Finally, expect to see transformational changes in life sciences and the way diseases are treated, leading a path to personalized medicine.
These Global inflections provide a great platform for the material science community to collaborate, work together and accelerate the required innovations
AlGaN/GaN HEMT device fabrication process is developed on 3-inch semi-insulating SiC substrate to achieve enhanced RF performance up to C-band for power applications with reliable and reproducible performance. MOCVD grown AlGaN/GaN HEMT structures with 2DEG density ~ 1013 cm-2 and electron mobility ~ 2000 cm2V-1s-1 are used for device fabrication. The device fabrication process sequence involved successful development and integration of unit processes like ohmic/Schottky metal contacts, SiN device passivation, multi-finger field plates, ICP-RIE mesa etching, air-bridge metal cross over interconnections, SiC through via-hole etc. The main process technology breakthroughs include the control over breakdown voltage and knee walkout after PECVD based SiN surface passivation through incorporation of TCAD designed field plate structures with minimal degradation in cut-off frequency. The designed field plate structures are integrated in AlGaN/GaN HEMT device through a well devised compatible process sequence on 3-inch wafer. The fabricated field plated HEMT (Fig.1) with 0.7µm gate length exhibited about three times improvement in breakdown voltage of device as a result of reduced peak electric field between gate and drain. The device off-state breakdown voltage is enhanced beyond 150V enabling higher VDS (drain to source voltage) operation and significantly improving RF output power with device cut-off frequency ~ 16GHz (Fig.2). Also various passive components (Fig.3) like square power inductors, circular inductors, MIM capacitors, transmission lines, mesa/NiCr resistors etc are also developed for MMIC applications
Since the invention of the semiconductor transistor in 1947, the phenomenal progress in electronics systems is enabled by the transistor scaling in the micro to nano regime coupled with very large scale to giga scale integration, driven by storage and compute applications. Today, the complex electronic systems quite often achieve first pass success from conception to deployment, thanks to mature CAD tools that help manage very diverse building blocks, with hierarchy of abstraction. However, the basic tenet of transistor scaling is staring at the red brick wall, due to scientific and technological challenges. It is contemplated that non CMOS architectures might drive the Moore’s law and enable future compute and storage systems, beyond the conventional scaling era.
In all this milieu, I believe that the stage is set for a new wave of electronics systems to be equipped by massive sensory functions, going beyond conventional compute and storage paradigm. However, not much attention is given to develop a holistic approach to manage the diversity and scaling issues of sensor blocks, akin to what was done in digital, analog and mixed signal electronics. I will present two case studies from my personal experience:
(i) Biosensor systems for point of care diagnostics : the story of managing the sensing of multiple analytes in blood and urine with an eventual goal to realize “Lab on Palm”
(ii) Gas sensor systems for environmental monitoring, breath analysis and hazardous gas leakage detection, with an eventual goal to realize the “Electronic Nose”
Navakanta Bhat received his B.E. in Electronics and Communication from SJCE, University of Mysore in 1989, M.Tech. in Microelectronics from I.I.T. Bombay in 1992 and Ph.D. in Electrical Engineering from Stanford University, Stanford, CA in 1996. Then he worked at Motorola’s Networking and Computing Systems Group under Advanced Products R&D Lab (APRDL) in Austin, TX until 1999. At Motorola he worked on logic technology development and he was responsible for developing high performance transistor design and dual gate oxide technology. He joined the Indian Institute of Science, Bangalore in 1999 where he is currently a Professor and Chair, Centre for Nano Science and Engineering. His current research is focused on Nanoelectronics device technology, Biosensors for point of care diagnostics and Gas sensors for pollution monitoring. He has 240 research publications in international journals and conferences and 10 granted US patents and 14 pending patents to his credit. He was instrumental in creating the National Nanofabrication Centre (NNfC) at IISc, Bangalore, benchmarked against the best university facilities in the world. He served as the chairman of NNfC administration committee from 2010 to 2015.
He is Fellow of the Indian National Academy of Engineering and Fellow of IEEE. He has received the Young Engineer Award (2003) from the Indian National Academy of Engineering, Swarnajayanti fellowship (2005) from the Department of Science and Technology, Govt. of India and Prof. Satish Dhavan award (2005) from the Govt. of Karnataka. He is also the recipient of IBM Faculty award 2007 and Outstanding Research Investigator award (2010) from DAE. For his translational research work, he has received Dr. Abdul Kalam Technology Innovation National Fellowship (2018), Prof. Rustum Choksi award for Excellence in Engineering Research (2017), Nina Saxena Technology Excellence award (2018), NASI Reliance Industries Platinum Jubilee award (2018) and BIRAC Innovator award (2018). He has also received the Infosys Prize (2018) for his contributions in Engineering and Computer Science category.
He is currently (2016-2019) a member of the Board of Governors of the IEEE Electron Devices Society and also the Chair of Nanotechnology technical committee. He was the Editor of IEEE Transactions on Electron Devices, (2013-2015), and the chief-editor of the IEEE TED special issue on “2D Materials for Electronic, Optoelectronic and Sensors”. He was the founding chair of the IEEE Electron Devices and Solid-State Circuits society, Bangalore chapter which was recognized as the Outstanding Chapter of the Year by the IEEE SSC society (2003) and IEEE EDS society (2005). He was the technical program chair for the International Conference on VLSI design and Embedded Systems (2007) and co-General chair of the International conference on Emerging Electronics (2012). He is a Distinguished Lecturer of the IEEE Electron Devices Society.
He was the Chairman of the Human Resource Development and Infrastructure committee of the National Program on Micro and Smart Systems. He was the member of the committee set up by the Principal Scientific Advisor to Govt. of India to recommend strategies to develop semiconductor manufacturing ecosystem in India.
He is the founder and promoter of a startup company, PathShodh Healthcare Pvt Ltd (www.pathshodh.com). Based on his group’s research in biosensors, PathShodh has developed the first of its kind multi-analyte point-of-care diagnostic device for 5 blood tests and 3 urine tests, related to multiple chronic diseases including diabetes and its complications, anemia and malnutrition, kidney and liver diseases. For this technology, PathShodh has received multiple recognitions : Confederation of Indian Industry (CII) Industrial Innovation Award 2017, for the most promising start-up and CII Grand Jury Award for Innovation, 2017; Federation of Indian Chambers of Commerce and Industry (FICCI) Healthcare Excellence award, 2017 for the best start-up of the year; Design Impact award for Social change by Titan. PathShodh’s product has already been used for rural health screening. Notable among them is the partnership with Tata Trust in deploying PathShodh technology for rural Telemedicine project serving several villages in Andhra Pradesh and Uttar Pradesh.
High-power fiber lasers have seen tremendous development in the last decade with output powers exceeding multiple kilowatts from a single fiber. However, power scaling has been largely confined to the narrow emission wavelength region of Ytterbium due to certain material advantages inherent to it. Other wavelength regions have lagged significantly and many applications rely upon the diversity of emission wavelengths. Currently, Cascaded Raman fiber lasers are the only known wavelength agile, scalable, high power fiber laser technology that can span the wavelength spectrum. In my talk, I address the technology of Cascaded Raman fiber lasers, specifically focused on the newer developments. Our recent work on making broadly tunable high-power cascaded Raman fiber lasers with near complete wavelength conversion will be discussed.
High power narrow linewidth sources find numerous applications such as coherent beam combining, LIDAR, and laser guide star. Power scaling of narrow linewidth source through fiber amplifiers is usually limited by nonlinear processes, specifically due to the onset of stimulated Brillouin scattering (SBS). In this talk, we will discuss the use of Karl-Pearson’s correlation coefficient to analyze the backscattered radiation resulting in early detection of the onset of SBS. We will also discuss the mitigation of SBS through controlled line broadening of a narrow linewidth source using a phase modulator driven with sinusoidal as well as “optimised” waveforms.
Optical beams of different spatial structures have attracted a great deal of interest due to their variety of applications in science and technology including atomic physics, plasma physics, trapping, micromachining, lithography, and high resolution microscopy. Typically, such optical beams are generated through the spatial modulation of Gaussian beams. In this talk, I will describe our recent results on high power parametric sources producing different structured beams including vortex beams, hollow Gaussian beams and Airy beams. The talk will also include some background on the origin of nonlinear optical effects, and the basics of the structured beams.
Fibre lasers have become the backbone of high power laser sources over the last decade. In order to fulfil the increasing demand of high output power from a fibre laser, there is a need for optical fibre which can provide large effective area (Aeff) of the fundamental mode (FM) to avoid non-linear effects while simultaneously offering high suppression to higher order modes to preserve the beam quality. This paper will review the fibre designs for mode area scaling and fibre fabrication techniques for future high-performance fibre laser systems.
This talk will cover a set of activities in optical systems at Bharat electronics limited.
The ability to accurately point a laser beam is becoming increasingly important [1]. The performance capability of a control system depend on how tightly light focus at target It has many applications, such as LIDAR, countermeasures, remote sensing, target illumination, micromachining and directed energy weapons.
The control system is composed of several assemblies to carry out multiple functions where software is also an essential component of the integrated system. The target engagement starts with a cueing sensor indicate the target location, and then the beam control switches to engagement mode, in which the operator lock the target with electro-optic tracking system (EOTS) integrated on the laser platform. Once the target is locked the EOTS will track the target and centered camera of EOTS. Then target is illuminated to carry out fine pointing with micro-radian accuracy through active imaging. Laser beam focusing at the target can be assisted by a laser range finder. The fine tracking of the target by high rate camera and associated image processor allows high precision servo control of the Fast Steering Mirror (FSM) for precise point the laser beam on the designated spot of the target.
This talk highlights technological challenges towards development control system for fine pointing of laser beam. The latest trends of using adaptive optics to improve beam control performance by correcting for atmospheric turbulence effects will be also presented along with the progress of the research carried out so far.
Modelocked fiber laser provides an ideal platform for generation of optical pulses in diverse temporal formats due to strong interplay of dispersion, self-phase modulation, spectral filtering, linear and nonlinear gain and losses. In this talk I shall present our recent work on generation and amplification of pulses from modelocked Yb-doped fiber laser in diverse temporal format including dispersion managed soliton, dissipative soliton, dissipative soliton resonance, chair-like pulses, step like pulses, bound pulses, burst of pulses and soliton rain. The physical basis of building such modelocked lasers and amplification characteristics of some of the pulse profiles will be discussed.
High efficiency, low thermal management problems, small footprint and above all high beam quality at high powers, make fiber lasers the most suitable choice for important applications in both civil and defence sectors. The talk would present recent achievements and challenges in the development of kilowatt-class CW and high peak power pulsed fiber lasers at LASTEC.
In the on-going era of autonomous vehicles and Internet of Things, the semiconductor industry has actively been developing embedded spin transfer torque (STT) magnetoresistive random access memory (e-MRAM), aiming for a variety of applications such as embedded flash, slow SRAM and Cache-like SRAM. This talk gives an overview of STT-MRAM technology and also the recent demonstration of GLOBALFOUNDRIES’ fully functional 40Mb e-MRAM macro based on 22nm FD-SOI platform using an optimized pMTJ stack which shows simultaneous reliability of data retention and endurance performances in the operating temperature range (-40 to 125°C). The time dependent dielectric breakdown mechanisms in ultra-thin MgO tunnel barrier will also be presented to make sure product reliability.
Vinayak Bharat Naik is a Member of Technical Staff at GLOBALFOUNDRIES, Singapore, where he is responsible for STT-MRAM device design and product reliability. From 2011 to 2014, he was associated with Data Storage Institute (A*STAR), Singapore as Scientist working on STT-MRAM development in a joint project with Micron Technology Inc., and also as Principal Investigator for E-field controlled MRAM project with National University of Singapore. Vinayak obtained his PhD degree in Physics from National University of Singapore in 2011. He has published more than 45 technical papers in international journals/conferences, and holds more than 15 U.S. patents. He has been serving as scientific reviewer for various American & European journals, and also executive committee member of various organizations including IEEE Magnetics Society.
Dr. Shivananda Wagle, Manipal Technologies Limited, Manipal.
Silver nanowire (AgNW) based flexible and transparent conducting films (TCFs) has attracted significant interest in the recent development for next-generation thin, lightweight, foldable and bendable electronic applications. This alternative approach overcomes the challenges associated with conventional Indium tin oxide (ITO) based TCFs such as high processing costs, inflexibility, and insufficiency of rare metals. The major advantages of AgNW based TCFs include ability to fabricate large area electronic devices with low manufacturing costs. Among the available coating technologies, micro gravure printing is widely considered to be one of the most promising process as it provides fine resolution of several microns with great uniformity over the large area. This printing technique provides easy scalability opportunities as well. In addition, the talk will also cover the details on optimization of ink formulation, roll to roll printing process and characterisation studies of the final coated flexible TCFs.
GM – R&D
Manipal Technologies Ltd.
Manipal-576104
Area Of Interest:
Synthetic Organic chemistry
Security Ink Formulation
Functional Inks
Printing
Education:
PhD – 2008 – National Institute of Technology Karnataka, Surathkal
MSc – 1998 – Mangalore University
Publication:
Research papers – 7
Patents – 2
Patent Applications – 4
S.H. Lau, has over 20 years’ experience in microscopy, material characterization and instrumentation in diverse applications from semiconductor failure analysis, material science research, geoscience and tissue engineering. A regular presenter at many international conferences, he also published several papers in material characterization and imaging in the field of X-ray Microscopy. He exited from Xradia after it was acquired by Carl Zeiss in 2013. He is now the Vice President of Business Development in Sigray Inc, which is pioneering the development of ultra brightness, tunable x-ray sources and advanced x-ray optics for lab instrumentation and synchrotron applications.
By coupling our patented tunable multi energy ultra-high brightness lab X-ray source with novel high efficiency x-ray optics, we have developed a suite of X-ray techniques with performance comparable with synchrotron, such as synchrotron-microXRF (s-uXRF) and X-ray Absorption Spectroscopy (XAS) with XANES (X-ray Near Edge Spectroscopy) and EXAFS( Extended X-ray Absorption Fine Structure).
XAS (with XANES and EXAFS) unlocks critical chemical state information, including: oxidation state, coordination environment, bond symmetry, and bond lengths. This is vital for determining the element’s potential for chemical activity and for understanding what interactions may have already potentially occurred during a process cycle. As the world’s only lab based commercial XAS system, the Sigray’s Quantum Leap has several innovations providing throughput and sub eV resolution comparable to results obtained from synchrotron XAS. This could help accelerate research gaps in functional characterization for a variety of critical materials, from catalysts, battery materials, electronic materials, fuel chemistries, corrosion and nanotechnology. As a non destructive technique capable of operating in vacuum or ambient, potential applications include in situ or characterization in operando of changes in valence states, example, monitoring changes in valence states during a battery charge discharge cycle. Several examples of data acquired in this laboratory system will be compared against published spectroscopic data obtained from synchrotron XAS.
With the advancement in nanomaterials, electronic and advanced materials, the need for fast, non-destructive compositional analysis of trace level composition of materials is increasing. This is evident in the semiconductor, solar and nanotechnology where thickness and composition of sub-atomic layered deposition is posing challenges in current metrology. This is driven by device scaling and new 3D architectures. The novel Sigray’s Attomap microXRF provides a rapid method to determine down to sub-angstrom equivalent thicknesses for thin films, ultra thin film stacks and dopant monitoring in 3D Finfet structures. System can also be used to characterize metal composition, metal layer thickness in Ni, Sn, Cu multistack microbumps applications in wafer packaging and TSV void localization. Results are compared to TEM.
The novel microXRF also provides rapid high resolution large area elemental mapping technique in various applications in material and life and geoscience at trace detection levels. This will be illustrated with contamination and aging applications in Li-ion battery industry; nanoprobes in drug delivery, trace level compositional applications at sub-ppm or high ppb concentration levels in metallomics or biological tissue, rare earth and precious mineral location in mining.
Other products in the pipeline from the synergy of coupling the ultra high brightness X-ray source and novel optics includes X-ray Microscopy (XRM) and Atmospheric XPS sources and optics.
References:
The inclusion of photovoltaic (PV) cells on flexible substrates for flexible electronic systems could allow building more sophisticated systems with improved capabilities. There is also the potential for commercial applications of stand-alone PV systems implemented on flexible substrates. Some of the advantages for flexible PV modules are light weight, devices conformal to surfaces and ease of storage, transport and deployment.
In this presentation, the gamut of PV technologies that can be made flexible or implemented on flexible substrates will be highlighted. Following this, the implementation of organic solar cells on flexible substrates at IIT Kanpur will briefly discussed. The possibility of using ternary hybrid hetero-junction structures to improve device efficiency by modifying an existing bulk-heterojunction process line will be presented with an example.
S. Sundar Kumar Iyer is a faculty member in the Department of Electrical Engineering at IIT Kanpur. His main area of research interest is organic solar cells. At the National Centre for Flexible Electronics, he and the FlexPV team are involved in building solar cells and modules on flexible substrates that can be used for practical electronic systems.
Prof. Praveen C Ramamurthy received M.Sc in Polymer science in 1995 from University of Mysore. He obtained his PhD degree from University of Clemson in the year 2004. He worked as a R&D Engineer in Therm-O-Disc, Mansfield, OH, USA and Research Scientist in Hoku Scientific, Honolulu, Hawaii, USA. He joined the Department of Materials Engineering, Indian Institute of Science (IISc), Bangalore, India in the year 2007. He is also Associate faculty in Centre for Nano Science and Engineering and Inter Disciplinary Centre for Energy Research, Indian Institute of Science, Bangalore, India. His current research focuses on organic electronics including synthesis of conjugated polymer for the application in photovoltaics, and sensors. Part of his research group works on materials for device package application and sensor for the organic volatile compound, heavy metals and biosensors. He has over 140 peer reviewed papers published and 18 patents to his credit.
Novel PV concepts like organic-inorganic metal halide perovskites and Silicon based heterojunction solar cells have emerged as potential candidates as low cost, high efficiency alternatives to c-Si technology. However, given the promises, several important system level concerns needs to be addressed for this emerging technology to become a mature technology – with issues ranging from the fundamental operating mechanism of the device, its theoretical efficiency limits, performance optimization pathways, and degradation mechanisms which contribute to device failure. Here, we describe the insights obtained through predictive modeling to address these important system level concerns.
Pradeep R. Nair received the B.Tech. degree in Electronics and Communication Engineering from National Institute of Technology Calicut, India, in 2002; the M.Tech. degree in Electrical Engineering from the Indian Institute of Technology (IIT), Bombay, Mumbai, India, in 2004; and the Ph.D. degree from the School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, USA, in 2009.
He joined the Dept. of Electrical Engineering, IIT Bombay, in Oct 2011, after two years of postdoctoral research at Purdue University. His research interests include modeling and simulation of electronic devices for healthcare and energy applications, semiconductor device physics and reliability, and nanoelectromechanical systems.
The semiconductor industry is going through a disruptive phase as scaling physical dimensions of transistors and interconnects while maintaining performance, power, area and cost improvements is becoming extremely untenable. This talk will cover some of these major trends and challenges at the bleeding edge of technology scaling, e.g., the 7nm and beyond technology nodes. Additionally, the talk will highlight some of the major areas of disruptive innovation, such as beyond CMOS devices and technologies, integration schemes such as 2.5D and high-density 3DIC, non-volatile memory technologies and the associated challenges of modeling and simulating these systems.
Dr. Siva Sivaram
Executive Vice President, Silicon Technology & Manufacturing Western Digital Corporation
__________________________________________________________________________________________________________
Dr. Siva Sivaram is an Executive Vice President at Western Digital, responsible for the company’s industry-leading NAND flash memories and other memory and storage technologies.
Sivaram has more than 35 years of experience in semiconductor industry and has held executive positions at Intel, Matrix Semiconductor and at SanDisk after its acquisition of Matrix. Additionally, he was Founder and CEO of Twin Creeks Technologies, a solar panel and equipment company.
Sivaram serves on the board of directors for the Global Semiconductor Alliance and the America-India Business Council. He is on the board of several start-up firms and was entrepreneur-in-residence at Crosslink Capital and XSeed Capital.
Sivaram has published numerous technical papers and a textbook on Chemical Vapor Deposition. He holds several patents in semiconductor and solar technologies.
He received his Doctorate and Master’s degree in materials science from the Rensselaer Polytechnic Institute, where he has been elected to its Board of Trustees. Additionally, Sivaram is a Distinguished Alumnus of the National Institute of Technology, Tiruchi, India, where he received his Bachelor’s degree in mechanical engineering.
Title: Quantum Simulations with Noisy Device
_______________________________________________________________________________________________________________________________
First impact of quantum information processing is expected in development of high precision sensors and simulations of few-body quantum systems. Given that the upcoming quantum devices will be noisy, it is necessary to devise techniques to make them error-resilient as well as to validate and verify their results. Development of hybrid quantum-classical algorithms for solving optimization problems, with tunable parameters that can be improved by feedback, is an attractive area of research. Another important area of investigation is the study of non-equilibrium quantum processes. Ongoing explorations in these directions will be described.
Title: Spin transfer and spin-orbit torques in magnetic multilayers
________________________________________________________________________________________________________________
Spin transfer torque (STT) and spin-orbit torque (SOT) allows manipulation of magnetization dynamics in magnetic multilayer heterostructures. John Slonczewski and L. Berger first predicted the spin transfer torque (STT) in the year 1996 [1] while spin-orbit torque (SOT) is a relatively newer concept. In this talk, I would summarize our recent works on STT and SOT. Using STT, I will numerically demonstrate a novel microwave oscillator based on the periodic rotation of a skyrmion in a thin magnetic nanodisk. Theoretical analysis based on Thiele’s formulation [2] is done to explain the origin of the rotation of skyrmion. We attribute the obtained phenomena of auto-oscillations of skyrmions to a possible synchronization between the breathing and rotational modes of the skyrmion. I will then discuss our recent experimental results of anti-damping SOT in Py/Ta system [3]. I will demonstrate a 30% current modulation of the Gilbert damping constant, in this system. Finally, I will discuss the possible origin of this large current modulation. References: 1. J. C. Slonczewski, J. Magn. Magn. Mater. 159, L1 (1996); L. Berger, Phys. Rev. B 54, 9353 (1996). 2. A. A. Thiele, Phys. Rev. Lett. 30, 230 (1973) 3. D. Tiwari, et al., Appl. Phys. Lett. 111, 232407 (2017).
Indian Institute of Science Education and Research (IISER), Pune 411008
_____________________________________________________________________________________________________________________________
That an ensemble of nuclear spins in ordinary liquids and solids at an ambient temperature allow precise manipulation of their quantum dynamics, retain quantum superpositions for long durations, and allow precise measurement of the final states is remarkable. Thanks to decades of methodology developments in nuclear magnetic resonance (NMR) spectroscopy, we can conveniently implement various quantum gates, algorithms, and simulations using nuclear-spin quantum processors controlled by amplitude and phase modulated radio frequency pulses. In this talk, after a brief introduction on nuclear spins and NMR, I will explain how one can initialize, control, and measure a set of spin-qubits. After describing some recent developments, I will point out certain limitations of NMR quantum processors and indicate potential solutions that have been proposed.
Title: Random access quantum information processing using multimode circuit quantum electrodynamics
__________________________________________________________________________________________________________________________________
Qubit connectivity is an important property of a quantum processor, with an ideal processor having random access — the ability of arbitrary qubit pairs to interact directly. We describe the implementation of a random access superconducting quantum information processor using multimode circuit quantum electrodynamics, demonstrating universal quantum gate operations on a nine-bit quantum memory. The memory uses the eigenmodes of a linear array of coupled superconducting resonators, with the qubits being superpositions of vacuum and single-photon states stored in them. These qubits are all controlled by a single superconducting transmon circuit coupled to the edge of the array, serving as the central processor. We show that single transmon charge control, and flux-driven sideband interactions with the cavity modes are sufficient for universal quantum control of the entire multimode manifold, demonstrating universal gate operations between arbitrary pairs of modes, and efficient schemes for generating multi-photon entangled states. I will describe recent efforts to realize this quantum computing architecture using high-Q 3D multimode superconducting microwave cavities with photon lifetimes exceeding a millisecond. I will additionally describe methods for enhancing photon lifetimes in a superconducting circuits by engineering transition matrix elements, and Raman schemes for realizing fast gate operations.
Quantum assisted sensing across length scales
_________________________________________________________________________________________________________________________
The development of point-like quantum sensors based on wide bandgap materials, for instance Nitrogen Vacancy (NV) centers in diamond, has thrown up exciting new possibilities for the sensing of materials, molecules and biological systems through optical means. In particular I will describe the development of “quantum-assisted” magnetic resonance probes based on the NV center that allows sensing of nano- and meso-scale volumes at high spatial and frequency resolution. I will also highlight an alternate use of the NV sensor as a means to create highly nonequilibrium spin populations in nuclear spin systems in order to “hyperpolarize” them, boosting their magnetic resonance signatures by several orders of magnitude. This allows quantum sensors to greatly enhance sensing capabilities of conventional macro-scale MRI and NMR, potentially enabling compelling possibilities such as the development of miniature spectrometer devices for high-throughput chemical analysis and imaging.
TRAM Floating Base Memory
______________________________________________________________________________________________________________
Several memory cell ideas based on a floating semiconductor region within a device have been published, including Thyristor-RAM, TCCT-Thin Capacitively Coupled Thyristor, floating body memory, Capacitorless DRAM and many more. Among these the cells based on a “bipolar mode” of operation can be called floating base vs. “FET mode” device named floating body. Since the FET has limited sensitivity to body potential, the floating body devices suffer from low read margin. Floating base devices like TRAM with bipolar operation are tricky to optimize. However, an 18Mb yeilding TRAM product chip has been reported. This is the highest density floating base memory reported. Further the TRAM has been shown to operate at 1ns read/write on silicon, among the highest demonstrated for these technologies. In this article we review the simplified principle of operation and key device features/optimization necessary to enable this technology.
AlGaN/GaN HEMT device fabrication process is developed on 3-inch semi-insulating SiC substrate to achieve enhanced RF performance up to C-band for power applications with reliable and reproducible performance. MOCVD grown AlGaN/GaN HEMT structures with 2DEG density ~ 1013 cm-2 and electron mobility ~ 2000 cm2V-1s-1 are used for device fabrication. The device fabrication process sequence involved successful development and integration of unit processes like ohmic/Schottky metal contacts, SiN device passivation, multi-finger field plates, ICP-RIE mesa etching, air-bridge metal cross over interconnections, SiC through via-hole etc. The main process technology breakthroughs include the control over breakdown voltage and knee walkout after PECVD based SiN surface passivation through incorporation of TCAD designed field plate structures with minimal degradation in cut-off frequency. The designed field plate structures are integrated in AlGaN/GaN HEMT device through a well devised compatible process sequence on 3-inch wafer. The fabricated field plated HEMT (Fig.1) with 0.7µm gate length exhibited about three times improvement in breakdown voltage of device as a result of reduced peak electric field between gate and drain. The device off-state breakdown voltage is enhanced beyond 150V enabling higher VDS (drain to source voltage) operation and significantly improving RF output power with device cut-off frequency ~ 16GHz (Fig.2). Also various passive components (Fig.3) like square power inductors, circular inductors, MIM capacitors, transmission lines, mesa/NiCr resistors etc are also developed for MMIC applications.
High efficiency, low thermal management problems, small footprint and above all high beam quality at high powers, make fiber lasers the most suitable choice for important applications in both civil and defence sectors. The talk would present recent achievements and challenges in the development of kilowatt-class CW and high peak power pulsed fiber lasers at LASTEC.
shri Hari Babu Srivastava, Outstanding Scientist and Director of Laser Science and Technology Centre (LASTEC), Delhi, is currently spearheading various technology and product development initiatives in the areas of high power lasers, laser spectroscopy and laser countermeasure applications. Prior to this, he has also worked in the areas of line of sight stabilization and electro-optical fire control and surveillance systems, leading multi-disciplinary teams towards development of equipment for Indian Armed Forces.
He is an alumnus of IIT Roorkee and IIT Kanpur from where he obtained his B.E. and M.Tech. degrees in Electrical Engineering, respectively. He is author/co-author of around 30 research papers, numerous DRDO reports and four technical books/chapters in English and Hindi. He is a recipient of DRDO Cash and Group Technology Awards for his contribution towards various DRDO programmes.
The ability to accurately point a laser beam is becoming increasingly important [1]. The performance capability of a control system depend on how tightly light focus at target It has many applications, such as LIDAR, countermeasures, remote sensing, target illumination, micromachining and directed energy weapons.
The control system is composed of several assemblies to carry out multiple functions where software is also an essential component of the integrated system. The target engagement starts with a cueing sensor indicate the target location, and then the beam control switches to engagement mode, in which the operator lock the target with electro-optic tracking system (EOTS) integrated on the laser platform. Once the target is locked the EOTS will track the target and centered camera of EOTS. Then target is illuminated to carry out fine pointing with micro-radian accuracy through active imaging. Laser beam focusing at the target can be assisted by a laser range finder. The fine tracking of the target by high rate camera and associated image processor allows high precision servo control of the Fast Steering Mirror (FSM) for precise point the laser beam on the designated spot of the target.
This talk highlights technological challenges towards development control system for fine pointing of laser beam. The latest trends of using adaptive optics to improve beam control performance by correcting for atmospheric turbulence effects will be also presented along with the progress of the research carried out so far.
This talk will cover a set of activities in optical systems at Bharat electronics limited.
Fibre lasers have become the backbone of high power laser sources over the last decade. In order to fulfil the increasing demand of high output power from a fibre laser, there is a need for optical fibre which can provide large effective area (Aeff) of the fundamental mode (FM) to avoid non-linear effects while simultaneously offering high suppression to higher order modes to preserve the beam quality. This paper will review the fibre designs for mode area scaling and fibre fabrication techniques for future high-performance fibre laser systems.
Title: III-V vertical nanowire FET & tunnel FET – fabrication and characterization
____________________________________________________________________________________________________________________________
III-V nanowires are attractive for device applications. The small nanowire footprint reduces the number of propagating defects opening a path for integration of high-quality III-V materials on Si. The direct band gap and the wide range of wave lengths addressable makes the material suitable for optoelectronic applications including light emitting diodes, solar cells, and long wave length photodetectors. The advantageous transport properties find usage in transistors applications where the reduced scattering enhances the drive current. The realization of such devices, requires processing strategies for structures with 10 nm dimensions and detailed material characterization to avoid detrimental parasitic effects on the device performance. In this talk, III-V nanowire MOSFETs and TunnelFETs will be presented and benchmarked towards Si MOSFETs. State-of-the-art performance in terms of transconductance (gm), drive current (Ion), subthreshold swing (S), and off-state leakage current (Ioff) will be demonstrated. In particular, we will focus on InAs/InGaAs MOSFETs and InAs/InGaAsSb/GaSb TunnelFETs, where the nanowire growth technology allows for incorporation of materials with strong lattice mismatch into the transistor channel. These heterostrucutures are essential for the III-V device performance.
Title: Intrinsic magnetism in monolayers of transition-metal tri-halides
_____________________________________________________________________________________________________________________________
Abstract: Two dimensional magnetic materials, with tunable electronic properties could lead to new spin- tronic, magnetic and magneto-optic applications. Here, we explore intrinsic magnetic ordering in two dimensional monolayers of transition metal tri-halides (MX3, M = V, Cr, Mn, Fe and Ni, and X = F, Cl, Br and I), using density functional theory. We find that other than FeX3 family which has an anti-ferromagnetic ground state, rest of the trihalides are ferromagnetic. Amongst these the VX3 and NiX3 family are found to have the highest magnetic transition temperature, beyond the room temperature. In terms of electronic properties, the tri-halides of Mn and Ni are either metals or Dirac half metals, while the tri-halides of V, Fe and Cr are insulators. Among all the tri-halides studied in this paper, we find the existence of very clean spin polarized Dirac half metallic state in MnF3, MnCl3, MnBr3, NiF3 and NiCl3. These spin polarized Dirac half metals will be immensely useful for spin-current generation and other spintronic applications.
Title: Atomically thin, layered, and 2D materials: Physics and Applications
________________________________________________________________________________________________________________________________
Abstract: In the past decade, there has been enormous progress in materials science and engineering at the very limits of quantum confinement. Ground-breaking discoveries and innovations have resulted from a range of atomically-thin systems such as carbon nanotubes, graphene, 2D transition metal dichalcogenides and other layered materials. These developments in ultrathin matter have spearheaded an explosive growth in new science and technology. In particular, their tunable electronic and optoelectronic properties make them extremely attractive for a host of applications. In this talk, we will discuss recent developments in the application of 2D materials such as graphene and other atomically thin materials and systems. By appropriately combining 2D and 3D architectures these materials can lead to advanced applications in a broad range of areas from tunable photodetection and light emission, high-performance energy harvesting and storage, ultra-high-frequency NEMS actuation, and DNA detection and analysis. The synthesis and advanced characterizations of these materials, along with device design, fabrication, characterizations, and computational and simulation/modeling of a variety of systems will be discussed. We will discuss our attempts to develop and manipulate new types of atomically-thin materials, exploring the behaviour of charge, photons and phonons in them, and utilizing their unique properties to develop applications in the nanoelectronics, optoelectronics, sensing, detection, actuation, energy, and other areas. Through these discussions, I will try to motivate how quantum matter can potentially transform several important applications and enable them to operate at ultra-high and unprecedented performances.
K.V. Reddy obtained an MSc in Chemistry in 1972 from the Indian Institute of Technology – Madras and a PhD in Physical Chemistry in 1977 from the University of Wisconsin, Madison, USA. He worked at three different corporate research labs in the United States prior to founding PriTel, Inc. in 1994. PriTel manufactures state-of-the-art test and measurement equipment for the fiber-optics telecommunications industry. PriTel made equipment can be found in every pre-eminent telecom research laboratory across the globe.
He is the President of PriTel, Inc. and he is also the current President of IITMAANA (Indian Institute of Technology – Madras Alumni Association of North America). He is also a major benefactor of IIT Madras, having funded a Chair in Photonics in the EE Department.
This talk will cover the process of product development in optical systems, taking a working laboratory prototype and taking it to the market with specific examples.
Dielectric meta-structures comprising of sub-wavelength dimension arrays of Group-IV and III-V semiconductor nanostructures on low-index substrates are attractive for realizing low loss, high performance and scalable frequency selective surfaces. The frequency selective performance is achieved using Mie scattering in isolated nanostructures and guide-mode resonances in closely spaced arrays. Such frequency selectively or resonant structures offer enhanced field concentration in the structure and the surrounding low-index material. This field enhancement can be used for enhanced light matter interaction to boost linear (fluorescence, absorption) and nonlinear optical processes. This talk will focus on the use of amorphous silicon nanodisk arrays and zero-contrast grating structures for resonant enhancement of third harmonic generation and four-wave mixing processes. The experimental work on the combined spectral, spatial and intensity dependent effects will be presented. The application of such meta-structures for realizing low form factor active photonic functionalities will also be discussed.
Varun Raghunathan received his Ph.D. in Electrical Engineering from University of California Los Angles (UCLA), in 2008, working with Prof. Bahram Jalali in the area of Silicon photonics. Then he worked at Ostendo Technologies, a start-up company based out of San Diego, CA USA in the area of III-Nitride LED arrays for pico-projector applications until 2009. He worked as a postdoctoral researcher at the Chemistry department at University of California Irvine from 2009-2012 with Prof. Eric Potma in the area of nonlinear optical microscopy. From 2012-2016 he worked as a research scientist at Agilent Research labs in Santa Clara, CA USA working on laser based infrared microscopy, developing optical imaging techniques for anatomic pathology and its clinical translation. He joined IISc as an Assistant Professor in 2016. His research interests are in nonlinear optics, integrated photonics and optical microscopy.
Thermally Activated Triplets Fusion as a Function of Polymer Chain Packing in Boosting the Efficiency of Organic Light Emitting Diodes:
____________________________________________________________________________________________________________________________________
Abstract:
Converting the dark states (triplet excitons) to emissive singlet without high Z material in efficient manner via controlling the solid state packing of fluorescent polymer chains in LEDs is discussed will be discussed in this talk. A mystery of ultrahigh efficiency of fluorescent donor-acceptor type co-polymer LEDs, demonstrated by us and others, is resolved by temperature dependent high sensitivity delayed emission spectroscopy with complimentary results on dispersed chains in inert matrix vs solid thin film.[1] Thermally activated triplet hopping in closely packed chains can increase triplet-triplet annihilation (TTA) induced singlet yield by many folds. These results were confirmed by scattering studies and quantum chemical calculations to strengthen the findings. Processing condition which allow us to make closely packed chains, showed more scattering due to restriction on twisting of chains, i.e., reduced dihedral angle. This could enhance triplet hopping and also boost the triplet density, hence TTA, by enhancing the singlet-triplet exchange energy. These results remarkably came in agreement with our quantum chemical calculation studies. A complete quantitative analysis for these PLEDs as a function of film thickness is carried out, which suggested closely packed chains have narrower singlet emission hence reduced singlet-triplet annihilation rate due to reduced spectral overlap, one of the known major loss mechanism in OLEDs. [2,3] This study provides not only fundamental understanding of this efficient device but also provide essential guidelines for device and molecular engineering for blue and red emitting organic semiconductors.
References:
1. “Kinetics of Thermally Activated Triplet Fusion as a Function of Polymer Chain Packing in boosting the Efficiency of Organic Light Emitting Diodes” A. Dey, N. Chandrasekaran, D. Chakraborty, P. Johari, C. R. McNeill, A. Rao and Dinesh Kabra Nature Flexible Electronics volume 2, Article number: 28 (2018)
2. “Role of Bimolecular Exciton Kinetics in Controlling the Efficiency of Organic Light Emitting Diodes” A. Dey and Dinesh Kabra ACS Appl. Mater. Interfaces, Volume 10, pp 38287–38293 (2018)
3. “A Complete Quantitative Analysis of Spatio-temporal Dynamics of Excitons in Functional Organic Light Emitting Diodes” Amrita Dey, Akshay Rao and Dinesh Kabra, Adv. Optical Mater. Vol. 5, p- 1600678 (2017)
Dipolar interaction mediated novel magnetic states in patterned magnetic nanostructures
______________________________________________________________________________________________________________________________
In this talk, we will discuss our results on the role of defects in artificially patterned two–dimensional single domain nanostructures with strong shape anisotropy. Such nanostructures mimic Ising-like macro-spins which when placed in a special arrangement exhibit two-in two-out type magnetic behavior under the influence of strong dipolar interactions and are called artificial spin ice (ASI) systems [1,2]. Recently, ASI systems have been given a significant attention in order to explore the physics of geometrical frustration arising from strong dipolar interactions between Ising-like macrospins [3,4]. We investigated in detail the behavior of such ASI systems in square geometry by introducing different types of defects in the ASI-vertices. An intricate interplay of defect and dipolar interaction in such systems is found to systematically stabilize a robust magnetic remanent state where magnetic monopole like scenario emerges at the vertex of a square-shaped ASI structure [5]. Magnetic force microscopy experiments of such nanostructures lithographically fabricated from permalloy thin films reveal spin ice structures at the vertices. Detailed analysis of the experimental and micromagnetic simulations will be discussed.
References:
[1] M. J. Harris et al., Phys. Rev. Lett. 79, 2554 (1997).
[2] R. F. Wang et al., Nature 439, 303 (2006).
[3] C. Nisoli et al, Rev. Mod. Phys. 85, 1473 (2013).
[4] L. J. Heyderman, J. Phys: Condens Matter 25, 363201 (2013
[5] N. Keswani and P. Das, AIP Advances 8, 101501 (2018).
Abstract:
Interfaces are proving to be a dominant factor in influencing transport studies in pseudo-magnetic nanostructures. The concept of ferromagnetism at interfaces has a new meaning1 with many exciting physics that is yet to be explored. Research activity in this direction has the potential to contribute to next generation memory, sensor and logic devices. In this talk, we highlight some of the exciting results covering a broad range of material classes, viz. organic molecules, ferromagnetic insulators, topological insulators, antiferromagnets and also superconductors2 to demonstrate the richness in these studies and discuss some of the recent research activities of our group in these directions.
References:
1. Materials chemistry: A magnetic facelift for non-magnetic metals, Nature 524, 42 (2015)
2. Probing pair-breaking mechanisms in proximity-induced hybrid superconducting interfaces, arXiv:1807.11665 (2018)
Title : GaN based nanowire transistors
GaN based transistors have attracted a lot of interest because of its immense potential for high power and RF applications. GaN based transistors are also being aggressively studied for various novel phenomena. The talk will discuss fabrication of AlGaN/GaN nanowire transistors and its various characteristics. The talk will particularly highlight the effect on the transport characteristics during the evolution of 1-D nanowire structures from 2-D systems.
EDUCATION
PROFESSIONAL Position
PROFESSIONAL ACTIVITIES (Recent yrs.)
PROFESSIONAL HONORS & AWARDS (Recent yrs.)
Scientific Publications (44+)
Atomic Force Microscope (AFM) has been widely used as it can provide various physical properties in nanometer scale in various sample and environmental conditions. Due to the recent development of automated AFM technology, the applications of AFM are extending industrial sectors such as Hard Disk Manufacturing and Semiconductor Industry. Especially, accurate measurement and analysis of micro-, nano-structures are becoming an utmost important issue due to the reduction in the size of semiconductor devices and its direct influence on the device performance. In addition, the limitations of equipment (CD-SED, TEM, OCD, etc.) used for microstructure measurement are growing, such as resolution limitations, sample damages caused by sample preparation and measurement, etc. The AFM’s capability of nondestructive nanostructure measurement and openness to hybrid metrology is attracting attention and is becoming one of the next generation in-line measurement solution. In tight collaboration with IMEC, a global research center for nanoelectronics, we have made rapid progress in the field of industrial automated AFM after announcing the joint development project for in-line AFM for semiconductor industry since 2015. Through joint development projects with IMEC and our own efforts, various Semiconductor AFM solutions have been developed to complement existing optical metrologies in process development, production, and defect analysis. New applications for measuring high resolution 3D AFM metrology are currently being explored. The potential AFM solutions in inline semiconductor process will be introduced.
One of the principal factors motivating the study of 2 dimensional semiconductors in insulating gate electron devices is the potential for 2D semiconductor systems to result in near ideal semiconductor/oxide interface properties. This talk will focus on the application of impedance spectroscopy (100Hz to 1 MHz) to the analysis of interface states and border traps in the oxide/MoS2 system using MOS and MOSFET structures. The experimental capacitance-voltage (CV) and conductance-voltage (GV) response over frequency and applied bias are analyzed in conjunction with physics based ac simulations to probe the density and energy distribution of oxide/MoS2 interface states and border traps in the oxide.
The CV and GV response of back gated p+Si/Al2O3/MoS2/Au capacitor structures, with relatively thick MoS2 (>200nm), exhibit a near ideal multi-frequency CV response in the depletion region. This provides experimental results to support low/negligible interface states in oxide/MoS2 structures for the case of MoS2 layers transferred to an amorphous Al2O3 surface. Results will also be presented for CV/GV gate-to-channel analysis of top gated n-type MoS2 MOSFET structures, based on thin channels (5-10 layers) and Al2O3 or HfO2 gate oxides formed on the MoS2 surface by atomic layer deposition. For the top gated MoS2 MOSFETs, multi-frequency CV/GV responses yield variable interface state density values over the range (5×1011 to 1×1013 cm-2eV-1), with the response of border traps in the Al2O3/HfO2 also evident for bias conditions corresponding to accumulation of the MoS2/oxide interface. Finally, results will be presented illustrating how oxide/MoS2 interface state density values in top gated MOSFETs are significantly reduced by forming gas (H2/N2) annealing at 300oC.
The authors acknowledge the financial support of Science Foundation Ireland under the IvP project INVEST (SFI-15/IA/3131), the US-Ireland R&D Partnership Programme (SFI/13/US/I2862) and the NSF UNITE US/Ireland R&D Partnership for support under NSF-ECCS–1407765.
Paul K. Hurley is a Senior Research Scientist at the Tyndall National Institute (www.tyndall.ie), and a Research Professor in the Department of Chemistry at University College Cork (www.ucc.ie). Paul leads a research team exploring alternative semiconductor materials and device structures aimed at improving the energy efficiency in the next generation of logic devices. In particular the group are working on III-V and 2D (e.g., MoS2, WSe2) semiconductors and their interfaces with metals and oxides which will form the heart of logic devices incorporating these materials. The group are also researching the use of metal-oxide-semiconductor (MOS) systems for the creation of solar fuels through water splitting reactions.
Wenbing Yun 1 , Benjamin Stripe 1 , SH Lau 1 , Srivatsan Seshadri 1 , Alan Lyon 1 , David Vine 1 , Sylvia
Lewis 1
1 Sigray, Inc. | Concord, CA
Synchrotron x-ray microanalytical techniques have now developed vital roles for research in
advanced semiconductors and materials, due to the high penetrating power and non-destructive
analytical capabilities of x-rays. The demand on these facilities have driven the construction of
several new synchrotron facility projects around the world [1] and the establishment of new
partnerships, such as the recent agreement for India to join as an associate member of the
European Synchrotron Radiation Facility (ESRF) [2].
There is significant desire for bringing synchrotron capabilities to individual laboratories, which
would provide the accessibility that could significantly accelerate research efforts. In the past few
years, several major breakthroughs in x-ray source and x-ray optic technology have enabled
laboratory x-ray system capabilities that were previously thought only possible at the synchrotron.
These include systems such as a sub-eV (down to 0.2 eV) energy resolution x-ray absorption
spectroscopy (XAS) system for analysis of chemical states and electron bond lengths,
measurement of thin films and dopants at sub-angstrom concentrations with a novel micro x-ray
fluorescence (microXRF) system, and a 40 nm 3D x-ray microscope (XRM).
We will first discuss the innovations, most notably a novel microstructured x-ray source that
enables substantially higher brightness and energy tunability through a multi-target anode
design. Additionally, the introduction of a novel double paraboloidal mirror lens design have
yielded a myriad of advantages over existing approaches, including superior brightness
preservation of ultrabright laboratory x-ray sources, larger working distances, achromatic nature,
and increased resolution.
Breakthrough application results obtained from laboratory systems enabled by these new x-ray
components will be shown. These include: non-destructive characterization of 3D fin-FETs with
1% repeatability, chemical and oxidation state determination of catalysts used in batteries as a
function of charge cycles (obtained within minutes), rapid compositional measurement of CIGS
solar cells, thin film thickness measurements of Ni mask residuals and Pt catalyst layers in
memory, and 3D structural characterization of V-NAND memory stacks. The use of such tools,
due to their non-destructive nature, as an upstream complement for nanoSIMS and FIB-TEM in a
central laboratory environment will be explored.
[1] https://www.nature.com/articles/nphoton.2015.76
[2] https://www.natureasia.com/en/nindia/article/10.1038/nindia.2017.69
Dr. Wenbing Yun is a leading researcher in X-ray imaging, an innovator, a serial entrepreneur, and OSA fellow. He has over sixty issued patents on x-ray technology. From 2000 to July 2013, he was founder, chief technology officer, and president (to 2009) of Xradia, Inc., a company specializing in high resolution x-ray microscopy. Under his leadership, the company established as a worldwide leader in high performance X-ray microscopes, growing profitably with over 100 people employment in the San Francisco bay area, and was successfully acquired by Carl ZEISS, a world leader in electron and optical microscopy as its X-ray Microscope Division. Post ZEISS’s acquisition of Xradia, Dr. Yun started Sigray, Inc. with a mission to make accessible the entire portfolio of synchrotron analytical techniques to laboratories worldwide. Sigray’s products include microXRF, XAS, and nano x-ray microscope systems and x-ray source and optics components.
Superconducting devices have emerged as one of the leading platforms for implementing quantum technologies. Cavity-optomechanical systems implemented with superconducting circuit elements have shown an exquisite control over the quantum states of massive-mechanical resonators. In this talk, I will initial results from an optomechanical platform based on a 3-dimensional waveguide cavity. In this system, we demonstrate a participation ratio of 43%, achieved by coupling a mechanical resonator to the modified electromagnetic mode. The optomechanical coupling is characterized by performing measurements in optomechanically-induced absorption limit. The low-impedance environment of our design offers the flexibility to incorporate a DC bias across the mechanical resonator, often a desired feature in tunable optomechanical devices. A pseudo-lumped nature of the electromagnetic mode in such a device, paves the way towards developing hybrid system with superconducting qubits, which has the potential to achieve control of massive oscillators down to a single-phonon, and to realize storage of the quantum information in mechanical vibrations.
Vibhor Singh is currently an assistant professor at the Indian Institute of Science Bangalore. He received his PhD degree from Tata Institute of Fundamental Research (Mumbai) in 2012. From 2012-15, he worked as a post-doctoral researcher at the Kavli Institute of Nanoscience, Technical University Delft (The Netherlands). His research interests include superconducting quantum devices, cavity-optomechanics, and electron-transport in low-dimensional device.
Printed electronic circuitry based on electrolyte-gated field effect transistors with inorganic oxide channel materials hold promise for high-performance, low power circuits for applications areas such as wearables, IoT, security keys or sensors. In order to integrate components such as individual, printed thin-film transistors (TFTs) into more complex circuits, the basic device properties, fabrication processes and integration concepts need to be characterized and understood. We show that we can build standard logic cells such as inverters, Nand- and Nor-Gates as well as benchmark circuits such as ring oscillators that show performances up to the kHz regime. In addition by using a modeling framework together with tested physical layouts all integrated into a printed process design kit, we can eventually simulate circuits such as ring oscillators, latches and physical unclonable functions with great accuracy and fabricate them on demand. As an outlook important capacitive effects resulting from the intrinsic device as well as the parasitic components together with new device concepts reducing parasitics will be discussed to further optimize the speed of printed circuitry.
Amit Verma received the Integrated M.Tech. degree in engineering physics from IIT-BHU, Varanasi, India, in 2010, and the Ph.D. degree in electrical engineering from the University of Notre Dame, IN, USA, in 2015. He has worked as a post-doctoral associate at Cornell University, Ithaca, USA and as a short term researcher at NUSNNI, Singapore. He is currently an Assistant Professor with the Department of Electrical Engineering, IIT Kanpur, India.
His research interests are in epitaxial growth and characterization of semiconductor thin films, semiconductor device design and fabrication, electron transport measurements and modelling.
β-Ga2O33 is an extreme wide bandgap oxide semiconductor with large energy bandgap of ~4.6-4.9eV and an estimated high breakdown field of ~7-8MV/cm. These excellent material properties are very promising to realize high-power devices. Furthermore, large area single
crystal β-Ga2O substrates can be grown using low cost melt-grown methods, which can
enable an economically feasible and high-efficiency power switching technology.
This talk presents first efforts to grow epitaxial thin films of β-Ga2O using a distilled-ozone source based molecular beam epitaxy (DO-MBE). Compared to oxygen plasma based MBE and normal ozone-MBE, DO-MBE provides comparatively more oxidizing conditions since each O33 molecule dissociates to give one oxygen radical. Effect of Ozone nozzle to substrate distance and growth pressure on Ga2O growth rate and crystal quality is presented. Enhanced oxidizing condition for smaller ozone nozzle to substrate distance enables thin film growth at higher substrate temperatures. DO-MBE growth of β-(AlGa)32O3 thin films is also presented.
Metal halide perovskites have emerged as a highly promising solar cell technology with high light to electricity power conversion efficiency and low processing cost due to their solution processability. However, to make perovskite solar cells commercially viable, particularly to compete with or build upon the traditional silicon dominated photovoltaic market, substantial progress is needed in improving their process techniques and scalability. Fabricating perovskite devices and modules in a roll-to-roll process on flexible substrates will enable high throughput manufacturing, and it will also allow the application space to be extended beyond what is available to rigid geometries. We investigated the performance of flexible perovskite solar cells with various transparent conductors, including indium tin oxides (ITO) and indium zinc oxides (IZO), on thin (100μm) flexible glass substrates. Progress of scaling up solution processed perovskites to larger areas, sheet-to-sheet and roll-to-roll, on flexible substrates and challenges with this will be discussed. For device structures of flexible glass/ITO/TiO2/mixed cation perovskites/Spiro-OMeTAD/MoOx/Al, sheet-to-sheet coated, a power conversion efficiency over 18% was demonstrated. For roll-to-roll coated devices, efficiencies over 14% have been achieved.
Maikel van Hest is a Senior Scientist in the Material Science Center at the National Renewable Energy Laboratory (NREL). He has 2 decades of R&D experience in photovoltaics. During this period, he has worked on a large number of photovoltaic absorber and contact materials. For the last decade his research has focused on solution processing of materials for photovoltaics, including scaling of these processes toward industrial scale through sheet-to-sheet and roll-to-roll fabrication. Dr. van Hest is the PI on several of NRELs industrial collaboration projects, with the goal of bringing developed technologies to market. He is also a co-PI on the NREL Core Perovskite Solar Cell Program. He was the recipient of two R&D 100 awards for solution-based CIS solar cells in 2008.ave been achieved.
Dr Rajendra Singh is presently an associate professor at the Department of Physics, IIT Delhi. He did M.Sc. (Physics) from D.B.S. College, Dehra Dun (affiliated to H.N.B. Garhwal University) in 1995. After that he joined Inter University Accelerator Centre (formerly Nuclear Science Centre), New Delhi for Ph.D. His Ph.D. work was related to the study of the effect of swift heavy ion irradiation on electrical properties of Si and GaAs. He completed his Ph.D. in 2001 with degree from Jawaharlal Nehru University, New Delhi. He then joined Walter Schottky Institute (WSI), Technical University of Munich (TUM), Germany as a post-doctoral fellow. There he worked on the design, fabrication and characterization of InP-based heterojunction bipolar transistors (HBTs). He extensively used Class 100 Cleanroom facilities at WSI working on various processing tools such as photolithography, wet etching, reactive ion etching, UHV metallization and rapid thermal annealing. In January 2004 he joined the Max Planck Institute of Microstructure Physics, Halle, Germany as a post-doctoral fellow. There he worked in the area of direct wafer bonding and layer splitting of semiconductors for the fabrication of silicon-on-insulator (SOI) and strained silicon-on-insulator (sSOI). He worked in a Class 10 Cleanroom facility at MPI Halle using processing tools such as wet benches, wafer bonding system, plasma enhanced chemical vapour deposition (PECVD) and annealing furnaces. There he also initiated activities on hydrogen implantation induced layer splitting (called as ion cut process) of GaN, AlN and ZnO. He joined the Department of Physics, IIT Delhi in November, 2006. At present he is Professor in the Department of Physics, IIT Delhi. His areas of interest are GaN based materials and devices, growth and characterization of semiconductor nanowires, wafer bonding and layer splitting of crystalline materials, graphene-semiconductor interfaces, and 2D materials and devices. He has about 110 publications in International Journals and a similar number of publications in conference proceedings/edited volumes/abstracts in National/International conferences and workshops. He is the recipient of MRSI Medal award for 2017
We present our work related to CVD growth of Ga2O3 nanostructures using CVD technique on various substrates and under various growth conditions. Various types of nanostructures such as nanowires, nanobelts and nanoflags were obtained under different growth conditions. We have carried out detailed characterization of these nanostructures using various techniques such as XRD, SEM, TEM, Raman spectroscopy, UV-vis absorption, cathodoluminescence and photoluminescence. The studies that we have performed in this interesting area of research are as follows:
(a) Comparative study of β-Ga2O3 nanowires growth on different substrates
(b) Iron-catalyzed growth of β-Ga2O3 nanowires on sapphire substrates
(c) Self-catalytic growth of β-Ga2O3 nanostructures on sapphire substrates
(d) Growth of Ga2O3-ZnO core-shell nanowires and their conversion into spinel ZnGa2O4 nanowires
(e) Study of photoconduction in β-Ga2O3 nanowires
(f) Growth of ultralong Ga2O3 nanowires and conversion to GaN nanowires using ammonification technique
References
GaN-based high electron mobility transistors (HEMTs) are very promising for high power and high frequency applications because of their outstanding properties. Realizing the significance of GaN based HEMT technology, indigenous development of the HEMT epi-material and device technology was initiated at SSPL. Material development was carried out by MOVPE on Sapphire and SiC substrate.
HEMT Epi-material technology has been successfully developed on SiC substrate. Epi-structures with mobility >2000 cm2V-1s1 with 2DEG density of 1×1013 cm-2 demonstrated over a large number of runs. The highest mobility achieved was 2250 cm2V-1s-1 with 2DEG density ~9.6×1012 cm-2. Typical surface roughness of 5µm×5µm AFM scan of HEMT structures was found to be 0.3 to 0.4 nm. Well resolved steps could be seen indicative of step flow growth and smooth surface. On-wafer uniformity and run-to-run repeatability of various characteristics has been achieved proving the capability and stability of the system and growth process for device quality material. The developed material characteristics are comparable to the state-of-the-art material technology worldwide, enabling the demonstration of GaN HEMT material technology at SSPL. The fabricated HEMT devices on indigenously grown materials resulted in power density of 4-5 W/mm.
Apart from the results achieved, the challenges and issues faced during development of growth process, effect of variation of various growth parameters on material properties would be discussed in this talk. Results of growth of high quality AlGaN barrier layer, GaN channel layer on device performance and some recent results of growth of InAlN based HEMT would also be presented.
Dr. Renu Tyagi is working as a scientist ‘G’ at solid state physics laboratory, Delhi. She completed her PhD in chemistry from Delhi university in 1987. She has worked on MOVPE growth of GaAs/AlGaAs based materials for solar cells and High power laser diode. Her current area of research has been on AlGaN/GaN HEMT material technology development on SiC substrate using MOVPE.
AlGaN/GaN/SiC High Power HEMT technology development encompasses development of material technology, unit process modules for device fabrication, integration of process modules, process characterisation and device measurement methodologies and active and passive device design/modeling.
Production of reproducible and reliable AlGaN/GaN/SiC High Power HEMT devices and MMICs requires certain benchmarking of each production stages for ensuring better yield and uniformity of device performance across a wafer and batch of wafers for Defence and Space applications.
The presentation will cover some of the significant considerations during technology development and production of AlGaN/GaN/SiC High Power HEMT devices and MMICs.
Presently, the Chief Executive Officer of GAETEC, India and is looking after production of GaAs based L-band to Ka-band MMIC and RF products and development of GaN based high power HEMT and MMIC technology for Ku band application.
Acquired MSc degree from university of Bombay (1986) and M Tech, from IIT Kharagpur (1988) in the area of Microelectronics and Semiconductor Material Technology. Joined SSPL, DRDO in 1988 as a Scientist and contributed to development of mm-wave devices and MMIC technology and Transfer of Technology for production. Published about 25 papers in international journals, more than 80 papers in national and international conferences/workshop and invited talks. Two-time recipient of ‘DRDO Path breaking Research Award’ (As a Member of the Team during Year 2000 and 2017) for ‘Development of 12GHz MMIC Technology and ‘Development of X-band GaN Power HEMT technology’ respectively. Also received, ‘ DRDO outstanding team work award in the year 2000. Twice received ‘Scientist of the year award’ in the year 1996 and 2013 and four ‘Technology group awards’ at Solid State Physics Laboratory, DRDO, Delhi.
Flexible and Stretchable Electronic devices are gaining huge attention of the researchers worldwide because of their innovative applications in several areas such as in health, energy, agriculture, environment etc. These electronic devices are not only electronically functional, but also have additional features of mechanical flexibility so that they can flex, stretch, roll and bend. Furthermore, by virtue of their capability to utilize low cost and easily available materials, economic processes, easiness in scaling up, they create a huge opportunity to innovate. At Plastic Electronics and Energy Laboratory at IIT Bombay, we are simultaneously developing and utilizing the novel schemes of fabrication of flexible and stretchable electronic devices and are exploring their applicability for portable and wearable biomedical sensors. We are also interested in developing sensors for Industrial Internet of Things in addition to developing devices such as thin film transistors (TFT) and solar cells. In this talk, I will give an overview about materials used, engineering approaches and processes that are cost effective, energy efficient and has the potential for large scale manufacturing, while showing the developments we made in the areas mentioned above.
is working as an Associate professor at Metallurgical Engineering and Material science (MEMS) department, Indian Institute of Technology Bombay (IITB), India. She received her Bachelors, Masters and Ph.D. degree in Materials and Metallurgical Engineering from IIT Kanpur in 2000, 2002 and 2007 respectively. Later she worked as a BK-21 Postdoctoral Fellow at Korea Advanced Institute of Science and Technology (KAIST), Korea and as an EPSRC Research Associate at Imperial College, London, U.K. in year 2008 and 2009, respectively. She was also with Department of Electrical Engineering, Seoul National University, Korea as BK Assistant Professor from 2009-2011. She is associated with National Center for Photovoltaic Research and Education, Center of Excellence in Nano electronics, IITB-Monash Research Academy (an initiative of IITB and Monash University) and Wadhwani Research Center for Bioengineering located at IIT Bombay, India. Her research interests are in the area of Flexible and Stretchable electronics, Wearable sensors for application in healthcare and energy applications. Her research activities are funded by competitive programs of Department of Science and Technology (DST), Government of India, The Indo-US Science and Technology Forum (IUSSTF), Scientific and Engineering Research Board (SERB), Wadhwani foundation, Biotechnology Industry Research Assistance Council (BIRAC), Tata Center for Technology and Design (TCTD) etc.
Yogesh Singh Chauhan is an associate professor at Indian Institute of Technology Kanpur (IITK), India. He was with Semiconductor Research & Development Center at IBM Bangalore during 2007 – 2010; Tokyo Institute of Technology in 2010; University of California Berkeley during 2010-2012; and ST Microelectronics during 2003-2004. He is the developer of industry standard BSIM-BULK (formerly BSIM6) model for bulk MOSFETs and ASM-HEMT model for GaN HEMTs. His group is also involved in developing compact models for FinFET, Nanosheet/Gate-All-Around FET, FDSOI transistors, Negative Capacitance FETs and 2D FETs.
He is the Editor of IEEE Transactions on Electron Devices and Distinguished Lecturer of the IEEE Electron Devices Society. He is the member of IEEE-EDS Compact Modeling Committee and fellow of Indian National Young Academy of Science (INYAS). He is the founding chairperson of IEEE Electron Devices Society U.P. chapter and Vice-chairperson of IEEE U.P. section. He has published more than 200 papers in international journals and conferences.
He received Ramanujan fellowship in 2012, IBM faculty award in 2013 and P. K. Kelkar fellowship in 2015, CNR Rao faculty award and Humboldt fellowship in 2018. His research interests are characterization, modeling, and simulation of semiconductor devices. He has served in the technical program committees of IEEE International Electron Devices Meeting (IEDM), IEEE International Conference on Simulation of Semiconductor Processes and Devices (SISPAD), IEEE European Solid-State Device Research Conference (ESSDERC), IEEE Electron Devices Technology and Manufacturing (EDTM), and IEEE International Conference on VLSI Design and International Conference on Embedded Systems.
Gallium Nitride (GaN) High Electron Mobility Transistors (HEMTs) and their associated RF and power-electronic applications have been a topic of aggressive academic and industrial research over the past couple of decades. This is due to the commendable level of performance promised by the GaN material system and the hetero-junction that it forms with AlGaN, leading to features such as high breakdown voltage, high mobility, high saturation velocity, high sheet carrier density, the ability to withstand high operating temperatures etc. In order to take full advantage of these properties and to translate them into viable circuit applications a fully robust and accurate GaN HEMT model is of prime importance. In this talk, I will present our Advance SPICE Model for GaN (ASM-GaN) for GaN-based power and RF devices. ASM-GaN has been recently selected as an industry standard compact model for SPICE simulation, by the world-wide compact model standardization committee, after more than five years of meticulous development and rigorous testing.
state-of-the Art RF application demands near perfect prediction of the product performance even before the very first silicon tapeout.
Designers want to get a accurate prediction of dc and small signal ac characteristic along with large and small signal non-linearity and their frequency dependence.
For LNAs such figure of merits are compression points, Intermodulation distortion; And for RF-switch it is higher Harmonics, off state isolation along with Ron-Coff frequency response.
To achieve stringent specifications set by the application space, RF SOI and Bulk technologies had broken the “classical” concept of MOSFET device operation, which eventually necessitates
a major overhaul in existing compact models. In this talk I will touch upon few such examples to highlight the shortcoming of industry standard models for RF application.
Anupam Dutta is a Senior Member Technical Staff (SMTS) in GlobalFoundries Inc. He is working in the areas of compact model development, process enhancement and device design for future RF applications like 5G, satellite communication, mmWave. He is also chairman of the BSIMSOI work group, where he manages BSIMSOI industry-academia interaction, facilitating Model code update, QA and release.
Prior to that he has spent an year as scientist/engineer in Indian Space Research Organization as VerilogA designer for image processing and cartographic satellites. Anupam obtained MS degree from Indian Institute of Technology, Kharagpur after completing his B.Tech in the Institute of Radio Physics and Electronics, Kolkata. He has published 5 conference and journal papers and holds 3 US patents.
The conventional approach to enhance the performance of scaled/emerging logic devices is to reduce the ON state resistance of constituent transistors. Historically, the effort was always focused on reducing the transistor’s “intrinsic resistance” rather than the metal lines connecting billions of transistors in a chip. We will show that going forward; the back-end metal resistance will be the bottleneck in device performance. A typical metal interconnect at the source, drain or gate of a transistor consists of very thin barrier metal layers to prevent electro-migration due high current density at the ON state of a transistor. The thickness of these barrier layers is very small and comparable or less than the mean free path of electrons in those metals. We argue that at this small length scale, Ohm’s law breaks down as carrier transport is quasi-ballistic. Using Landauer’s approach, we will try to convince you that the metal-metal interface resistance becomes the dominant component of the total ON state resistance. The origin of this resistance is the “quantum mechanical” is due to the mode mismatch between two conductors.
Aniruddha Konar is a Senior Member of Technical Staff (SMTS) at GLOBALFOUNDRIES, Bangalore, India, where he works on technology development of Advanced technology. He has held positions in IBM Semiconductor R&D Center, Bangalore, India. He holds a PhD degree from University Notre Dame, USA and has published several technical pares and patents. Device Physics, device and process modeling, TCAD, ab-initio and analytical modeling are his main areas of expertise.
The healthcare scenario in India indicates the need for low-cost point-of-care diagnostic technologies. And flexible electronics can provide a platform for realizing such technologies. A brief overview of point-of-care and wearable technologies will be provided. Then an overview of the sensor activities in the FlexE Centre/SCDT @ IIT Kanpur will be presented. There is a growing interest in “Point-of-Care” (PoC) technologies for disease diagnostics using body fluids. A vast population not having an easy access to the diagnostic centers, due to the prohibitive costs and to the locational issues, adds to the burden of the disease in India. With a low level of healthcare facilities, there is a need for decentralization of the diagnostic tests and technologies for home testing or point-of-care testing could possibly alleviate some of the burden on the healthcare system. While blood has been a traditional body fluid to test for disease, breath and sweat are also being investigated. This talk will present some aspects of the works on body fluids which could lead to PoC devices.
Dr. Siddhartha Panda is currently a Professor of Chemical Engineering, the Golden Jubilee Chair on Entrepreneurship and Innovation, a participating faculty in the Materials Science Programme, and the Coordinator of the National Centre for Flexible Electronics (NCFlexE), at IIT Kanpur. His research focuses on chemical sensors for healthcare applications and the accompanying transport, reactions, transductions and materials processing, utilizing silicon and flexible printable platforms. Prior to joining IIT Kanpur, he was a Staff/Advisory Engineer at the IBM Semiconductor R&D Center, New York, for over six years. He obtained a Ph.D. from the University of Houston in 1999, an M.S. from the University of Cincinnati in 1995 and a B.Tech. from IIT Kharagpur in 1992, all in Chemical Engineering.
With improvement in micro and nanofabrication processes, researchers are able to control the growth and fabrication of single or arrays of nanotubes or nanofibres. While single walled carbon nanotube (SWCNT) and double walled carbon nanotube (DWCNT) are used for designing resonators, others used them in the form of arrays such as vertically aligned carbon nanotubes (VACNTs) to increases the surface areas for other applications. When nanotubes are used as vertically aligned form, the bulk properties change with respect to single SWCNT or DWCNT as these tubes are bonded together with interatomic non-bonded potential such as the van der Waals interactions. Moreover, under a given compressive loads, VACNTs buckle under different buckling load. Therefore, it is imperative to understand the variation of elastic and buckling properties of VACNTs with number of tubes under the presence of van der Waals potential between the neighbouring tubes. Since, the properties of SWCNTs and MWCNTs also depend on their configuration, the effect of configuration on elastic and buckling properties are also analyzed.
In order to use excellent properties of carbon to improve the properties of other planer structures such as microelectromechanical system (MEMS) or nanoelectromechanical system (NEMS), many graphene based MEMS/NEMS devices are explored. Thus, fracture properties and elastic properties of graphene silicon composites need to be investigated under different configuration of graphene and different crystallographic conditions of silicon. Additionally, we also investigate the size effect on elastic properties of graphene-silicon nanocomposites. After finding mechanical properties under static condition, we also perform the vibrational analysis of graphene-silicon and horizontally aligned carbon nanotube-silicon composites with and without surface effects. Finally, we investigate the performance of nanofibers in tuning the frequency of MEMS devices.
Dr. Ashok Kumar Pandey is currently an Associate Professor in the Department of Mechanical and Aerospace Engineering, Indian Institute of Technology Hyderabad. He completed his Masters and PhD from Indian Institute of Science, Bangalore in 2004 and 2008, respectively. He did his postdoctoral research from Technion-Israel Institute of Technology, Haifa, Israel from 2008 to 2010. He is also a recipient of best teaching award from IIT Hyderabad and Hetenyi Award from Society of Experimental Mechanics, USA. His interest lies in linear and nonlinear vibration, MEMS, Vehicle Dynamics.
is currently an Associate Professor in the Department of Mechanical and Aerospace Engineering, Indian Institute of Technology Hyderabad. He completed his Masters and PhD from Indian Institute of Science, Bangalore in 2004 and 2008, respectively. He did his postdoctoral research from Technion-Israel Institute of Technology, Haifa, Israel from 2008 to 2010. He is also a recipient of best teaching award from IIT Hyderabad and Hetenyi Award from Society of Experimental Mechanics, USA. His interest lies in linear and nonlinear vibration, MEMS, Vehicle Dynamics.
Interest in beta-phase gallium oxide (b-Ga2O3) is continuing to expand due to the rapid advances made in both material quality and in early stage transistor performance for this ~ 4.8 eV bandgap semiconductor. As with all wide bandgap semiconductor technologies, defects that contribute deep levels in the large bandgap are expected to have significant impact on device characteristics through effects such as carrier compensation, time-dependent carrier trapping and emission, persistent effects, and increased leakage currents. For b-Ga2O3, not only is a wide range of native point defects expected for this monoclinic crystal, but impurity–related defects due to the current state of maturity in bulk and epitaxial crystal growth are not fully understood. In an effort to build toward an identification of physical sources for deep levels, this presentation provides a comparison between the introduction of deep level defects by growth method variations and by post-growth high-energy particle irradiation, through characterization of materials structures and of completed transistors using defect spectroscopy methods. Deep level optical spectroscopy (DLOS) and thermally-based deep level transient spectroscopy (DLTS) methods applied to b-Ga2O3 transistors are shown to distinguish between traps due to impurities versus those that are probably due to native vacancies, even though the activation energies of these traps can be quite similar, within < 0.1 eV. This differentiation was corroborated by DLTS and DLOS measurements made before and after neutron irradiation on Schottky diodes. The ability to identify specific traps with either native defect types or impurities is critical to inform both growth optimization and future device designs.
High-power fiber lasers have seen astonishingly rapid progress over the last decade in a wide range of configurations, spectral ranges, and temporal formats, and are now leading contenders for many important applications like material processing (marking, engraving, scribing, welding, cutting etc), additive manufacturing, automobile, consumer electronics, medical and other sectors requiring power levels from a few watts up to many kilowatts. Though the fiber laser technology becoming one of the cutting-edge technologies, some criticalities are still there in high power level, namely modulation instability (MI), photodarkening (PD) effect, non-linearity and thermal management. All these issues will be discussed in the talk. The indigenously developed fiber laser technology will fulfill the requirement of desired specifications of the end-users. I will present our current as well as futuristic activities on fabrication of the specialty laser fiber and fiber based components for prototype laser modules development.
Mrinmay Pal did M. Tech in Optics & Opto-electronics from Calcutta University and received Ph.D from Jadavpur University, India. He joined as a Scientist on February, 2001 at CSIR-Central Glass & Ceramic Research Institute (CSIR-CGCRI), Kolkata. He has done work on development of fiber lasers and amplifiers, and Supercontinuum source for industrial and biomedical applications with industry collaboration. He fabricated and characterized different types of fibers (PCF, Leakage Channel Fiber) under international collaborative projects. His research interest is in ultra-fast fiber laser technology and generation of novel laser sources at UV-VIS-Mid-IR regimes. He spent 4 months (April to July, 2015) as Visiting Fellow at Optoelectronics Research Centre, University of Southampton, UK under Raman Research Fellowship and did work on generation of high pulse energy Yb-fiber laser. He has published more than 100 numbers of research papers in journals and conference proceedings as author and co-author and holding two US patents on fabrication of rare-earth doped fibers. Dr. Pal is a senior member of Optical Society of America (2006) and life member of Optical Society of India.
Neural membrane potential fluctuation need to be detected in neurons at single cell resolution, possibly from any structure of the brain, in order to advance microscale understanding of brain structure and function. Currently, no technique (fMRI, MEG, Electrophysiology) other than in-vivo two-photon calcium imaging achieves the desired resolution, however only within <1mm from the brain surface. Nitrogen-Vacancy centers (NVC) in diamond allow bio-magnetic field (like action potential associated magnetic field; APMF) imaging, due to its ultrahigh magnetic field sensitivity, microscale spatial and temporal resolution and room temperature operation. In this talk I will discuss our efforts towards realistic modeling of signals from cortical pyramidal neurons. Further, I will discuss a method for 3D image reconstruction of neurons using wide-field vector magnetometry via NV centers in diamond.
Physical properties of cells, such as, size, shape and deformability could be used as potential biomarkers to screen for diseases. My research group uses microfluidic technology to probe the physical properties of red blood cells to diagnose different blood-related disorders. In this talk I will briefly discuss two of our ongoing projects. The first project describes a microfluidics and mobile microscopy platform to detect sickle cell disease at the point of care. The second project describes a radial pillar-based platform (RAPID) to handle whole blood for several hours in a microfluidic device.
Debjani Paul is an associate professor at the Department of Biosciences and Bioengineering in Indian Institute of Technology Bombay. She obtained a Ph.D. in Physics from the Indian Institute of Science, Bangalore in 2005. She spent the next two years as a postdoc in Curie Institute, working on lamination-based microfluidic devices. During a second postdoctoral stint at the University of Cambridge, Debjani focused on electrical biosensors to detect protein-protein interactions and the biophysical mechanisms of salmonella infection in macrophages.
Her research group in IIT Bombay uses microfluidic technology to develop affordable diagnostic platforms and to explore biophysical phenomena under microfluidic confinement. Some of the ongoing projects in her lab are tuberculosis screening using a paperfluidic platform, detection of sickle cell disease, microfluidic cell sorting, population dynamics of bacterial colonies, etc.
The projects are funded by IIT Bombay, Department of Biotechnology (Innovative Young Biotechnologist Award), Centre for Nanoelectronics (Phase 2), Bill and Melinda Gates Foundation, Tata Centre for Technology and Design, and Wadhwani Research Centre for Bioengineering.
More details about her lab can be found at http://www.bio.iitb.ac.in/~dpaul/.
Ashwin Tulapurkar is Professor at the Electrical Engineering Department of IIT-Bombay. He obtained his B. Tech. in Engineering Physics from IIT-B and Ph.D. in Physics from Tata Institute of Fundamental Research (TIFR). He started working on spintronic devices at the National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan. He continued spintronics research at the Stanford Linear Accelerator Center (SLAC), USA and later at Osaka University, Japan before joining IIT-B. His current research interests include spin-based phenomena and magnetic materials.
Spin torque has emerged as a leading candidate for manipulations of spins in a nano-magnet. Spin torque is generated by the absorption of transverse spin current by a nano-magnet. Spin-current can be generated by passing electrical current through a non-magnetic material with high spin-orbit coupling via the spin-Hall effect. Here we show that heat current through a non-magnetic material can generate spin current via the spin-Nernst effect. We fabricated a multi-terminal device with Ni contact on a Pt. We applied thermal gradient cross Pt, and measured the voltage across Ni as a function of magnetic field. The electric voltage depends on the magnetization direction of Ni shows that spin current is generated by thermal gradient across Pt. This is a direct proof of the spin-Nernst effect. Further, we used this spin current to manipulate the magnetization dynamics via spin-Nernst torque.
[1] S. Meyer et.al., Nat. Mater. 16, 977 (2017).
[2] P. Sheng et.al., Sci. Adv. 3, e1701503 (2017).
[3] D. J. Kim, et.al., Nat. Commun. 8, 1400 (2017).
[4] Control of magnetization dynamics by spin Nernst torque, A. Bose et.al., Phys. Rev. B. (to be published).
[5] “Direct detection of spin Nernst effect in platinum”, A. Bose at.al., Applied Physics Letters, 112, 162401 (2018)
In the realm of next generation computing, chalcogenide based Phase Change Memory (PCM) offers promising features for a ‘universal memory’ owing to all-round characteristics including high-speed and non-volatility [1-3]. However, realizing an ultrafast switching is still a key challenge for faster programming. This talk will present exhaustive experimental results on electrical switching of Ge-Sb-Te, Ag, In-doped Sb2Te and In-Sb-Te based PCM devices including ultrafast electrical switching dynamics, voltage-dependent transient characteristics in picosecond timescale using a custom-built advanced programmable electrical test setup [4-9]. Furthermore, a trajectory map for defining the ultimate speed of PCM devices will be discussed on the basis of field-dependent transient dynamics in picosecond timescale [6-9]. This map is developed based on a systematic understanding of the voltage-dependent, time-resolved transient characteristics using voltage pulses of various short pulse-widths (full width half maximum, FWHM) down to 1.5 ns. Our experimental results show that the delay time, td decreases exponentially for increasing the applied voltage, VA above the threshold voltage, VT. With sufficient over-voltage, the device switches remarkably fast at its VT, revealing an ideal ‘zero-delay-time’. On the other hand, Ag, In doped Sb2Te device reveals a strikingly different threshold switching behavior at VT without delay (sub-50 ps). The switching speed is primarily governed by the rate of VT and it is independent of VA. These novel findings of unique switching behavior of Ag, In-doped Sb2Te and the trajectory map for enabling the ultimate speed of PCM devices would pave a way towards realizing ‘universal memory’ for future computing.
References
[1] M. Wuttig and N. Yamada, Nat. Mater. 6, 824 (2007).
[2] P. Hosseini, C.D. Wright, and H. Bhaskaran, Nature 511, 206 (2014).
[3] D. Loke, T. H. Lee, W. J. Wang, L. P. Shi, R. Zhao, Y. C. Yeo, T. C. Chong, and S.
R. Elliot, Science 336, 1566 (2012).
[4] M. Anbarasu, M. Wimmer, G. Bruns, M. Salinga, and M. Wuttig, Appl. Phys. Lett.
100, 143505 (2012).
[5] M. Anbarasu, M.S. Kumar, M. Kumaraswamy, S. Sahu and R. Ranjith, Appl. Phys.
Lett. 105, 243501 (2014).
[6] S. K. Pandey and M. Anbarasu Appl. Phys. Lett. 108, 233501 (2016).
[7] K. D. Shukla, N. Saxena, D. Suresh and M. Anbarasu, Sci. Rep. 6, 37868 (2016).
[8] S. Sahu, R. Sharma, K. V. Adarsh, and M. Anbarasu, Opt. Lett. 42, 2503 (2017).
[9] K. D. Shukla, N. Saxena and M. Anbarasu, Rev. Sci. Instrum. 88, 123906 (2017).
Dr. M. Anbarasu graduated in Electrical and Electronics Engineering from Bharathiar University Coimbatore. He received Ph.D. from Indian Institute of Science, Bangalore in 2008, for which he was awarded Dr. Srinivasa Rao Krishnamurthy Medal for the best Ph.D. thesis in the year 2007-08 at the Indian Institute of Science. He, then worked as a Post-Doctoral Fellow at the Department of Instrumentation, Indian Institute of Science for more than 1 year. During this tenure, he worked as a Research staff at Heriot-Watt University, UK under UKIERI Project. From September 2009 to August 2011 for two years, he worked as Alexander von Humboldt Post-Doctoral Fellow with Prof. Dr. Matthias Wuttig, at the I. Institute of Physics, RWTH Aachen University Germany, on the topic of ‘a systematic investigation of compositional dependence of electrical switching dynamics in phase change materials’. From March 2012, he has been working as a faculty member at IIT Indore, where currently he is an Associate Professor (since June 2016) of Electrical Engineering.
Dr. Anbarasu’s research interest includes design and development of high speed, phase change memory (PCM) devices for next generation high-speed Non-Volatile Random Access Memory (NVRAM) applications. This primarily involves in understanding ultrafast electrical switching dynamics, sub-ns programming characteristics of chalcogenide based phase change materials, and development of novel Ovonic Threshold Switch (OTS) selector devices for vertically stackable cross-point arrays for high-density memory solutions.
Dr. Adarsh K. V. is an Associate Professor at the Department of Physics, Indian Institute of Science Education and Research Bhopal (IISER), India. He obtained MSc in Physics from IIT Madras (2002) and Ph.D. in Physics from the Indian Institute of Science Bangalore (2007), India. After several years of postdoctoral research experience at the University of Rostock, Germany and Technion- Israel Institute of technology, Israel, he joined IISER Bhopal as Assistant professor in 2009 and promoted to Associate Professor in 2015. He was honoured with National Academy of Sciences (India) Platinum Jubilee Young Scientist Award in 2014, and elected as the Young Associate of the Indian Academy of Sciences in 2014. He is also an Editorial Board Member of the Scientific Reports (an open access journal from Nature Publication Group).
By using ultrafast time-resolved transient absorption (TA) measurements, we have studied the trapped carrier induced Stark shift, bandgap renormalization and exciton recombination by Schokley-Reed-Hall (SRH) effect in the free-standing MoS2 nanosheet colloidal suspensions prepared by liquid phase exfoliation. TA spectra at different excitation fluence reveal characteristic second-derivative type spectral features, suggesting carrier-density-dependent (scales linearly) blueshift and broadening of A and B excitons. Strikingly, exciton recombination at low excitation fluence occurs through trap states by first order SRH, however, taken over by bimolecular non-geminate recombination at higher fluence. Similarly, the decay kinetics of defects show that above a critical fluence, the created exciton densities are sufficient to saturate the fast decaying trap states.
Transition metal dichalcogenides (TMDCs) forms a unique class of layered semiconductors that are at the focus of intense experimental and theoretical research due to their rich physics and exceptional device potentials which are complementary to graphene. For example, TMDCs show strong electron-photon coupling owing to band nesting, strong quantum confinement effects, spin orbit coupling provide promising platforms for fundamental studies with potential applications in optoelectronics and valleytronics. Interestingly, TMDCs show direct bandgap in the monolayer limit and have highly stable neutral and charged excitonic states, even at room temperature. It is found that the exciton binding energies in TMDCs are many orders higher than the conventional Ga, In and As based 2D materials due to reduced dielectric screening. The behaviors of these excitonic quasi-particles play a vital role in determining the photophysical properties of TMDCs.
MoS2 nanosheets were prepared by probe sonication. Using ultrafast TA measurements, we fully characterize the spectral features of exciton many-body interactions in MoS2 nanosheets. We have observed the strong time and carrier density dependent blueshift (~47 meV) and broadening (~25 meV) of A and B exciton resonances, which is accompanied by bandgap renormalization that is estimated to be 4.5×10-10 eV cm2/3. Temporal characteristics of the TA reveal that the exciton recombination takes place by first order SRH process at lower carrier density, which is overwhelmed by second order bimolecular non-geminate recombination above the critical density (n0>36×1013 cm-2). Further, the decay of TSA below the A excitonic transition follows a biexponential model in which the amplitude of the fast decay component dominates at the lower carrier density and is over taken by slower component at higher carrier density. Our results provide important fundamental insight into the nature of exciton many-body interactions in MoS2 nanosheets and are of crucial importance in designing the optoelectronic systems based on TMDC nanoshebeen successfully uploaded, you will be sent a confirmation.
The current CMOS technology has been reaching its limits. It is facing big challenges and these obstacles will further increase with miniaturization. It will become extremely difficult to sustain the Moore’s law in the future. There is a pressing need to explore alternative technologies with capabilities to augment CMOS or to replace it altogether. Electronics primarily deals with the movement of charges which requires high power consumption. The electron also has a Spin property which has not been exploited for a long time. The devices which uses this property for computation has emerged recently with an enormous potential to augment the capabilities of CMOS. These spin devices have small form factor and are implemented in the interconnection layers without any Si area overhead using the existing CMOS infrastructure. Magnetic tunnel junction (MTJ), a basic spin device, consists of two ferromagnetic layers separated by a thin insulating MgO layer. One ferromagnetic layer has fixed magnetization whereas the magnetization of free ferromagnetic layer may be changed. The magnetization of the free ferromagnetic layer of MTJ is switched in both the directions with respect to the fixed layer magnetization by passing a bidirectional current. An MTJ offers different resistances depending upon the direction of magnetization of the free layer with respect to the fixed layer. This non-volatile dual resistance property can be used to design energy and area efficient circuits by the combination of MTJ and CMOS. This talk will present the design of logic and memory circuits using this hybrid technology
Prof. Mohd. Hasan received the B.Tech. degree in Electronics Engineering from Aligarh Muslim University, Aligarh, the M.Tech. degree in Integrated Electronics and Circuits from the Indian Institute of Technology Delhi, India, and the Ph.D. degree on “Low-Power Architectures for Multicarrier Systems” under a Commonwealth Scholarship, from the University of Edinburgh, U.K.. He has been a Full Professor at AMU since 2005. He was also a Visiting Postdoctoral Researcher on a project funded by the prestigious Royal Academy of Engineering, U.K., on “Low power field programmable gate array (FPGA) architecture” with the School of Engineering, University of Edinburgh. He is the author of more than 145 research papers in reputed journals and conference proceedings that includes 12 IEEE Transactions and 30 other ISI indexed journal publications along with four filed Indian patents on low power magnetic memories/SRAM. He has delivered several Keynote addresses and invited talks in Conferences and Workshops. He received best International Journal paper and many best International Conference paper awards. His research interests include Low Power VLSI Design, Spintronics, Nanoelectronics, Battery-less Electronics.
Soiling of PV module surface is an important energy loss mechanism in PV systems installed in India. In this paper, we would present results from our field and laboratory studies on the impact of soiling on energy yield in PV systems. An overview of the potential solutions being investigated would also be outlined.
Anil Kottantharayil received the Dr.Ing. degree (summa cum laude) from the Universitat der Bundeswehr, Munich, Germany, in 2002. From 2001 to 2006, he was with the Interuniversity Microelectronics Centre, Leuven, Belgium, where he worked on FinFETs, metal gate, and high-κ integration in logic technologies. Since 2006, he has been with the Department of Electrical Engineering, Indian Institute of Technology Bombay, where he is currently a Professor. His research interests are in the areas of novel MOS devices, memory technologies, graphene based devices, and silicon-based solar cells and modules. He has authored or co-authored more than 100 papers and conference presentations in these fields. He is a distinguished lecturer of the IEEE Electron Devices Society and a Fellow of the Indian National Academy of Engineering.
Dr. Chetan Singh Solanki, besides being a Professor at the Department of Energy Science and Engineering, IIT Bombay is also an educator, innovator, educator, researcher, entrepreneur, author and philosopher, known for his remarkable work in the solar sector.
Prof. Solanki was born in a small village called Nemit in the Khargone district of Madhya Pradesh. His primary school had just one class room and a teacher at that time. Having studied in the light of the kerosene lamp himself, Prof. Solanki is now committed to providing clean light to all. He received his Ph.D. from IMEC (Ketholik University) Leuven, Belgium, a leading R&D and innovation hub in micro and nano-electronics.
He is currently leading two projects of national importance on the dissemination of affordable solar technology. The National Center for Photovoltaic Research and Education (NCPRE) houses one of the best research facilities on Photovoltaic (PV) technology in India. It is funded by the MNRE, Govt. of India, to provide R&D and education support for India’s ambitious 100 GW solar mission. Prof. Solanki is one of the Principal Investigators at the center. Prof. Solanki is also the Principal Investigator in the Solar Urja through Localization for Sustainability (SoULS) project at IIT Bombay, which aims to provide solar study lamp to every child in rural India as part of its ‘Right to Light’ mission.
He also started kWatt Solutions Pvt. Ltd. which is a technology driven company focusing on energy optimization and technology customization to provide economic renewable energy solutions by developing and nurturing a network of entrepreneurs.
Dr. Solanki has taken several initiatives at social front as well. He is the founder of Education Park, an initiative in school education, which provides “high quality and affordable education & training in rural India”. Education Park has been built through public support with unique solar passive infrastructure, and its 14 acre campus runs on 100% solar energy. He founded ROSE, an organization for supporting education in rural India during his doctoral study in Belgium.
Dr. Solanki’s SoULS project implemented in Rajasthan received the Prime Minister’s award from Honorable Prime Minister Shri Narendra Modi in April 2017 under ‘Innovative Project’ category. He has won the European Material Research Society’s young scientist award in 2003 and IIT Bombay’s Young Investigator Award in 2009. He has published over 100 research papers in reputed international journals. He has 4 US patents to his credit with several more under review. He is a member of several national committees related to on Solar Technology. Prof. Solanki has authored 4 books on solar and renewable energy. One of his books titled, ‘Renewable Energy Technologies—A Practical Guide for Beginners’ (Hindi) got the first prize from the Ministry of New and Renewable Energy (MNRE), Govt. of India in 2011.
Dr. Solanki believes in practicing yoga, breathing exercises and
SDG-7 aims to provide clean, affordable, reliable and modern electricity access to all by 2030. There are nearly a billion around the world who do not have access. The question is not only how we can achieve the SDG goal but more importantly, how we are going to sustain it in times to come? IIT Bombay has evolved a concept of Solar Ecosystem by locals for locals (SELL) through large scale field implementations. Over 2.5 million households in India have got benefited from these efforts. The SELL or localized ecosystem envisages creating an interconnected network with localized consumption, localized supply and services, localized financing and even manufacturing. These efforts have also received Prime Minister’s award for innovation. The seminar discusses the concepts and practices required for providing quick, cost-effective and reliable energy access.
Next-generation electronic devices will necessarily feature novel materials, heterostructures, and nanostructures. Therefore, their design will need to be informed by materials modeling. In this talk, I shall illustrate the use of atomistic materials modeling for three very different device applications. The first is interface engineering for contacts to an alternate transistor channel material, namely germanium. The second is bilayers of two-dimensional materials for future device applications. The third relates to the quest for a truly biomimetic quantum electronic nose sensor.
Swaroop Ganguly got his BTech from IIT Kharagpur, followed by MS and PhD from UT Austin. Thereafter, he held R&D positions at UT Austin, Freescale, Tokyo Electron and IMEC before joining IIT Bombay in 2009, where he is now Associate Professor, PI of the Centre of Excellence in Nanoelectronics, and Co-PI of the Research Park. He has over 100 publications in peer-reviewed journals and international conferences in the broad area of nanoelectronic devices
Soumya Dutta received his Master in Physics from The University of Burdwan, India and Ph.D. degree from Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Bangalore, India in 2006. He received Young Scientist Award in “European Materials Research Society-2004”. He was a recipient of ICTP-TRIL fellowship, Italy to conduct postdoctoral research at CNR, Bologna, Italy between 2006 and 2007. In 2007, he joined The University of Texas at Austin, USA as a Research Associate. He has been selected in Marquis Who’s Who in America 2012 Edition as a recognized Research Scientist. He has published his scientific contributions in renowned international journals and proceedings, has filed 5 patents. He is an author of a book and a co-author of a book chapter. He is a member of Materials Research Society and IEEE Electron Device Society. Since 2011, he has been serving as an Assistant Professor in the Department of Electrical Engineering, IIT Madras. His current research interests include organic semiconductor based thin film transistors, solar cells, and photo-transistors, polymer based SAW devices and graphene based NEMS devices.
Microelectronic technology has been considered as an indispensable route for fabrication of electronic devices towards miniaturization along with scalable, high speed and large volume production, which essentially reduce the production cost. However, implementation of photolithography directly on the soft materials, which are essential candidates for flexible electronics, is not straight forward due to the compatibility issue. Our research group actively involves in the development of various electronic devices using solution based soft materials like polymer dielectrics, polymer piezoelectric materials, reduced graphene oxide (rGO) etc. by adapting microelectronic technology especially photolithography technique to realize miniaturized high resolution device structure.
In this presentation, three different device structures based on soft flexible materials that require sub-10 µm feature size will be discussed. The first device is piezoelectric polymer based surface acoustic wave (SAW) devices, which integrates the generation, propagation and detection of acoustic waves into the same device. The operating principle of SAW device, consisting of two interdigitated metal transducers (IDT), is to generate acoustic wave at input IDTs due to the transduction of applied electric signal to mechanical signal and to propagate to the output IDTs, where the mechanical signal is transduced to electrical signal to be detected. The operating frequency of SAW device depends on the spacing between IDTs. High operating frequency, which is required for higher sensitivity, demands sub-10 µm IDTs. The second class of device is rGO based nanoelectromechanical system (NEMS) device in which a rGO membrane, suspended between two metal pillars, is subjected to oscillate at resonance frequency. Effective operation requires low resolution feature size, which is not possible by any means other than microelectronic technology. The third set of devices is bottom gate bottom contact organic thin film transistor (OTFT) on polymeric dielectric materials. Since the organic semiconductors typically show lower mobility, it is highly required to minimize the channel length, leading to the increase in maximum switching frequency, which is defined as f_max≈(μ.V_ds)⁄L^2 (where μ,V_ds and L are mobility, drain-source voltage and channel length respectively). The major bottleneck of inclusion of polymer dielectric is the lack of consistency and compatibility of the polymeric material with lithography process.
This talk will enlighten the challenges to adapt microelectronic technology for shrinking the feature size, as prerequisite for the mentioned device structures and the possible solutions to overcome the issues, leading to scalable, reproducible, large volume production of flexible electronic devices.
Dr. Abhisek Dixit obtained PhD and MTech degrees in 2007 abd 2002 from IMEC/KULeuven and IIT Bombay respectively. From 2007 to 2013 he was with IBM SRDC. He joined Department of Electrical Enginnering IIT Delhi in 2013, where he is currently an associate professor. Dr. Dixit has more than 60 research publications and 4 patents in the field of FinFET device technology. He is a senior member of IEEE SINCE 2013.
Research results related to characterisation and modeling of CMOS devices will be discussed.
It is well known that mere conformance to IEC 61215 qualification test standard does not guarantee a 25 year service life for PV modules. National Centre for Photovoltaic Research and Education (NCPRE), IIT Bombay has performed All India Surveys of PV Module Reliability in 2013, 2014, 2016 and 2018 to identify key reliability issues faced by PV modules in field. The presentation will provide overviews of degradation rates seen in hot climates vs non-hot climates, large vs small systems, rooftops vs ground mount systems, new vs old modules etc in the All India Survey 2018 and comparison with previous surveys. Recommendations for improving the quality and reliability of PV power plants will be presented.
Dr. Narendra Shiradkar is a faculty member at Department of Electrical Engineering, IIT Bombay and leads the PV Reliability Group of National Center for Photovotlaic Research and Education (NCPRE). He is also the co-leader of the Task Group 4 of International PV Quality Assurance Task Force (PVQAT) working on bypass diodes and junction boxes. Before joining IIT Bombay, he has worked at the PV Division of Jabil Circuit Inc, USA as Photovoltaic Research Engineer for about 3 years and he has a PhD in PV Reliability from Florida Solar Energy Center, USA.
The Optoelectronic Materials and Devices group led by Dr. Aswani Yella at IIT Bombay has been involved in developing hybrid perovskite materials and photovoltaic devices since 2016; currently reaching efficiencies of ca. 13% with the well known methylammonium lead iodide perovskite based small area devices. Our group is involved in improving the stability of these perovskite based solar cells using two different approaches. One is to develop alternative absorber materials since the methyl ammonium lead iodide is inherently unstable. And the second approach is to develop interface layers, which influence the stability of the methyl ammonium lead iodide perovskites[1].
Before joining IITB, Dr. Aswani Yella carried out extensive research on the synthesis of various nanomaterials, quantum dots and applied the synthesized materials for photovoltaic applications. During the doctoral studies at Johannes Gutenberg University in Mainz under the guidance of Prof. Wolfgang Tremel, she has developed new synthetic routes for the synthesis of various chalcogenide nanomaterials. Not only the synthesis of the materials, PI also investigated the formation mechanism of these nanomaterials by carrying out insitu TEM studies. During the post-doctoral studies at the laboratory of photonics and interfaces headed by Prof. Michael Grätzel, EPFL, Switzerland, she has worked on dye/semiconductor sensitized solar cells and gained experience in various device fabrications and various architectures[2-4]. This expertise that the PI has gained, on the synthesis of nanomaterials, quantum dots, etc as well as on the various device fabrications in various architectures will help in executing this proposal successfully.
Hybrid perovskites have attracted much attention as a promising photovoltaic material in the past few years. Typically these hybrid perovskites like methyl ammonium lead halides (MAPbX3) undergo dimensionality reduction from 3-D to 0-D and finally to PbX2 upon continuous moisture exposure. We found that 0-D perovskite related structures exhibit reversible transformation from transparent state to colored 3-D state upon exposure to humidity. Fluorescence imaging of individual microcrystals revealed that the structural phase transition could be visualized in solid state, where in the shape of the crystals transform to cubic crystals. The plausible reason for this transformation is proposed to be a dynamic dissolution and recrystallization of the excess methyl ammonium halide (MAX) with varying humidity. The thermal and the moisture stability were found to be greatly enhanced in the transformed 3-D perovskite. Excellent device stability was also demonstrated when the devices were kept under moist (~70 %RH) conditions.
GaN technology is an ever-expanding topic of research and development, proving its potential to solve several challenges in power conversion that cannot be addressed by Si. For instance, medium voltage (650-900V) devices using the HEMT configuration have been able to reduce form factor at the system level by driving circuits at higher frequencies (100KhZ-1Mhz) and eliminating heat sinks or reducing cooling requirements. This alone sparked the interest in GaN research to save space, energy and ultimately cost of power conversion. However, in power conversion high current is a standard need, which requires a viable path for device scaling relying on a high quality and scalable substrate development and supply. Particularly when the market is favorable towards electrification of cars and other means of transportations, GaN must expand its scope to provide high power solutions with higher power density compared to Si, as well as SiC. Vertical devices have been the choice of power device engineers for economic use of the material and maximum use of its physical properties (which allow highest possible blocking field, field mobility, etc.). GaN vertical devices, therefore, carry all the advantages offered by vertical geometry and are being explored increasingly with emphasis on material and device needs. In this presentation we will discuss two flavors of vertical devices one of which requires regrowth and the other does not, to achieve their functionality.
CAVETs were designed to unite the best of both worlds- lateral (in the form he high mobility channel offered by AlGaN/GaN interface) and vertical (in the form of a thick n-GaN drift region). However as the blocking voltage increases towards 1.2kV, a MOSFET like structure starts to gain more advantage over a CAVET. While both of these device structures require some level of regrowth, a regrowth-free device is realized in a Static Induction transistor (SIT). We will discuss the latest results and current challenges in these devices and their applicability across various voltage ranges.
What lies beyond GaN? This is a critical question we need to answer in order to address the requirements of tomorrow’s grid and related power electronics. In my talk, I will establish the need for Ultra-wide bandgap semiconductors, with particular reference to Diamond where we have achieved over 1KV performance in diodes.
Prof Chowdhury’s group focuses on materials and device research for RF and Power electronics. Her academic career was launched at UCSB as a PhD student developing Vertcial GaN-based transistors. Vertical GaN technology has matured substantially over the last decade and she continues to contribute to the field by developing novel power switching devices. Besides GaN, her group works extensively on Diamond material and device development for high temperature electronics.
She has received the NSF CAREER, AFOSR Young Investigator Program (YIP) and DARPA Young Faculty Award (YFA) in 2015. She received the Young Scientist Award at the International Symposium on Compound Semiconductor (ISCS) in 2016 for her contribution towards GaN-Vertical device development. She is currently an associate professor in the ECE department at UC Davis, and joining the faculty in the department of Electrical Engineering at Stanford University in Jan, 2019.
The CMOS scaling is now facing serious fundamental and technological challenges resulting in diminishing performance and economic returns. The concurrent reduction in power consumption, an important aspect of scaling, has become difficult, because of the inability to reduce supply voltage below 1 V. This is primarily because the fundamental nature of charge transport governed by Boltzmann’s statistics restricts the Sub-threshold Swing (SS, abruptness between OFF to ON transitions) of FETs to the thermionic limit of 60 mV/dec at room temperature. Hence, as we cram in more transistors into the same footprint, energy dissipation and heat management have become fundamental bottlenecks. Clearly, the road ahead needs breakthroughs in new materials and device design.
In this talk, I will present the opportunities for CMOS scaling with 2D materials. In particular I will discuss about a new device architecture to beat the Boltzmann limit. We demonstrate, for the first time, sub-thermionic transport through tunable Schottky contacts in dual gated MoS2 FETs. Two device configurations the gate tunable thermionic tunnel transistor (GT3) and dynamic Vt and adaptable transport transistor (DVAT) are expounded. The GT3 transistor has the flexibility to operate either in the sub-thermionic tunnel regime, yielding steep SS<60 mV/dec OR thermionic high mobility regime. Combining the best of both tunnelling and thermionic regimes in the same operation cycle, the DVAT transistor, the closest to an ‘ideal transistor’, registers SS~29 mV/dec (3 dec) AND high mobility (100 cm2V-1s-1). This work is envisioned to pave a new path in the development of sub-thermionic, high performance FETs operating in the sub-0.5 V ‘green computing’ regime.
Navakanta Bhat received his B.E. in Electronics and Communication from SJCE, University of Mysore in 1989, M.Tech. in Microelectronics from I.I.T. Bombay in 1992 and Ph.D. in Electrical Engineering from Stanford University, Stanford, CA in 1996. Then he worked at Motorola’s Networking and Computing Systems Group under Advanced Products R&D Lab (APRDL) in Austin, TX until 1999. At Motorola he worked on logic technology development and he was responsible for developing high performance transistor design and dual gate oxide technology. He joined the Indian Institute of Science, Bangalore in 1999 where he is currently a Professor and Chair, Centre for Nano Science and Engineering. His current research is focused on Nanoelectronics device technology, Biosensors for point of care diagnostics and Gas sensors for pollution monitoring. He has 240 research publications in international journals and conferences and 10 granted US patents and 14 pending patents to his credit. He was instrumental in creating the National Nanofabrication Centre (NNfC) at IISc, Bangalore, benchmarked against the best university facilities in the world. He served as the chairman of NNfC administration committee from 2010 to 2015.
He is a Fellow of the Indian National Academy of Engineering. He has received the Young Engineer Award (2003) from the Indian National Academy of Engineering, Swarnajayanti fellowship (2005) from the Department of Science and Technology, Govt. of India and Prof. Satish Dhavan award (2005) from the Govt. of Karnataka. He is also the recipient of IBM Faculty award 2007 and Outstanding Research Investigator award (2010) from DAE. For his translational research work, he has received the prestigious Dr. Abdul Kalam Technology Innovation National Fellowship (2018), Prof. Rustum Choksi award for Excellence in Engineering Research (2017), Nina Saxena Technology Excellence award (2018), NASI Reliance Industries Platinum Jubilee award (2018) and BIRAC Innovator award (2018).
He is a senior member of IEEE, and is currently (2016-2019) a member of the Board of Governors of the IEEE Electron Devices Society and also the Chair of Nanotechnology technical committee. He was the Editor of IEEE Transactions on Electron Devices, (2013-2015), and the chief-editor of the IEEE TED special issue on “2D Materials for Electronic, Optoelectronic and Sensors”. He was the founding chair of the IEEE Electron Devices and Solid-State Circuits society, Bangalore chapter which was recognized as the Outstanding Chapter of the Year by the IEEE SSC society (2003) and IEEE EDS society (2005). He was the technical program chair for the International Conference on VLSI design and Embedded Systems (2007) and co-General chair of the International conference on Emerging Electronics (2012). He is a Distinguished Lecturer of the IEEE Electron Devices Society.
He was the Chairman of the Human Resource Development and Infrastructure committee of the National Program on Micro and Smart Systems. He was the member of the committee set up by the Principal Scientific Advisor to Govt. of India to recommend strategies to develop semiconductor manufacturing ecosystem in India.
He is the founder and promoter of a startup company, PathShodh Healthcare Pvt Ltd (www.pathshodh.com). Based on his group’s research in biosensors, PathShodh has developed the first of its kind multi-analyte point-of-care diagnostic device for 5 blood tests and 3 urine tests, related to multiple chronic diseases including diabetes and its complications, anemia and malnutrition, kidney and liver diseases. For this technology, PathShodh has received multiple recognitions : Confederation of Indian Industry (CII) Industrial Innovation Award 2017, for the most promising start-up and CII Grand Jury Award for Innovation, 2017; Federation of Indian Chambers of Commerce and Industry (FICCI) Healthcare Excellence award, 2017 for the best start-up of the year; Design Impact award for Social change by Titan. PathShodh’s product has already been used for rural health screening. Notable among them is the partnership with Tata Trust in deploying PathShodh technology for rural Telemedicine project serving several villages in Andhra Pradesh and Uttar Pradesh.
Deleep R. Nair received the Ph.D. degree in Electrical Engineering from IIT Bombay in 2005. He was a Senior Engineer at IBM SRDC, Hopewell Junction, NY, USA, involved in low-power logic technology development. He has been with Department of Electrical Engineering, IIT Madras, Chennai, India since 2012 where he is now an Associate Professor.
SiGe channel FETs were introduced in high volume manufacturing in 2011. In this talk, I will cover the history of SiGe channel transistors, some of its main challenges (which also includes our work) and its future prospects for sub 10nm nodes.
Ultraviolet sources based on III-Nitride materials find applications in various domains, including water purification, medical instrumentation and polymer curing. UV sources emitting ~ 240nm find use in the detection of chemical and biological agents. While AlGaN alloys are uniquely suited for these devices, due to the lack of a shallow p-type dopant for the necessary high Al-content, electrically injected devices are challenging. An alternate path lies in miniaturized electron-beam pumped devices, where an active region consists of a stack of AlGaN quantum wells.
In this work we investigated AlGaN MQWs grown by MBE, designed to emit at ~ 240nm. All structures consist of an AlN buffer layer, an AlGaN layer with ~80% AlN mole fraction, and 40 pairs of 2nm thick AlGaN Quantum wells with 3.5nm AlN barriers. Variations were made in the group-III to group-V flux ratio employed. Additionally, in some samples the well and barrier layers were exposed to an active nitrogen plasma after deposition. The internal quantum efficiency was estimated from Photoluminescence measurements.
Our results indicate that with variation of growth kinetics, IQE values can be increased from 11% to 45%. Furthermore, this IQE variation was found relatively uncorrelated with the interface abruptness of the wells and barriers as measured by XRD. We link these results to deliberately introduced nanoscale potential fluctuations in the alloy.
Anirban Bhattacharyya was born in Orissa, India. He obtained his B. Sc. Degree in physics from St. Xavier’s College Calcutta, India and M. Sc. Degree in electronic science from the University of Calcutta, India in 1993 and 1995 respectively. After spending a year at the Indian Association for the Cultivation of Science Calcutta as Junior Research Fellow, he joined the M. Tech. in materials science program at IIT Kanpur, India and obtained his degree in 1999. Subsequently he moved to the Wide Band-gap Semiconductors Laboratory at Boston University (USA) for his doctoral research. He received his Ph. D. in electrical engineering from Boston University in 2005 under the supervision of Prof. Theodore D. Moustakas. He continued at Boston University till 2009 working as a Senior Research Associate. In 2009, he joined the University of Calcutta as Assistant Professor at the Institute of Radio Physics and Electronics. His research interests include growth of III-Nitride materials by Molecular Beam Epitaxy and development of ultraviolet optoelectronic devices. He has over 70 research publications and one US Patent.
GaN based HEMTs are very attractive for both high power and high frequency applications due to the favourable material properties of GaN. However, there are two major challenges associated with GaN-based HEMTs : high gate leakage current (IG) due to Schottky gate and normally-on device operation due to the presence of 2-DEG even at zero gate bias. To reduce IG, a gate insulator layer is generally added to form metal-insulator-semiconductor HEMTs (MIS-HEMTs).
In this talk, we shall discuss about GaN-based MISHEMTs using Al2O3 as gate dielectric, deposited by different techniques. It will be shown that depending on the process conditions, the threshold voltage of the MIS-HEMTs can be modulated. Interestingly, it was found that with increase in tox, initially VTh shifts in the positive direction, followed by a negative shift, when Al2O3 is deposited by reactive ion sputtering. A comprehensive analytical model has been developed to explain this variation of VTh with tox, with an assumption that sputtered Al2O3 has negative fixed oxide charge at/near the interface and positive fixed oxide charge at the bulk of the oxide. This hypothesis is also supported by X-ray Photoelectron Spectroscopy (XPS) results. On the other hand, when an aluminum layer is deposited by e-beam evaporation and then oxidized using an indigenous high-pressure oxidation system, the shift in VTh is negative. Significant reduction in IG, high gm and Ion/Ioff ratio have been achieved for both these sets of devices.
Nandita DasGupta received her B.E. degree in Electronics and Telecommunication Engineering from Jadavpur University, Kolkata, India in 1982, M.Tech. in Electrical Engineering and Ph.D degrees from I.I.T. Madras in 1984 and 1988 respectively. She was awarded Alexander von Humboldt Fellowship in 1991 and spent one year in Technische Hochschule Darmstadt, Germany. Since 1993, she has been a Faculty member in the Department of Electrical Engineering, I.I.T. Madras and is currently a Professor. Her research interest is in the area of Semiconductor Device Technology and Modeling as well as Micro-Electro-Mechanical Systems (MEMS) and photonics. She has published more than 150 papers in international journals and conferences, coauthored a book and several book chapters.
Exploration of novel material with exotic property has become mandatory for energy scaling in semiconductor industry. Introduction of any new material in the process integration phase of technology development has however always been an expensive and time consuming affair. Thus, a modeling framework, that enables systematic performance evaluation of new materials at device and circuit levels before entering into capital-intensive manufacturing phase, is in great demand. Such models must be first principles based so that the assessment could be conducted even before the wafer is available. In this talk, which is focussed towards 2D materials, we discuss such multiscale modeling techniques, which starts from the atomic granularity of the material and ends up in SPICE. Using this methodology We demonstrate how an atomic level phenomenon (e.g. band-gap opening in graphene) could be translated into a circuit performance metric (e.g. frequency of a ring oscillator).
Santanu Mahapatra is working as a full professor in Department of Electronic Systems Engineering (formerly CEDT), at Indian Institute of Science (IISc), Bangalore, India. His research team is engaged in modeling of carrier transports in nano materials at circuit, device and atomistic level. His research interests include two dimensional channel transistors, energy efficient electronic switches and energy-storage at nano-scale. He is the recipient of Ramanna Fellowship (2012 to 2015) in the discipline of electrical sciences from Department of Science and Technology, Government of India for his contribution in compact modeling.
He is a senior member of IEEE (Electron Devices Society) and an adjunct faculty member of IIIT-Allahabad.
Vijay completed his Bachelors degree in Physics from St. Stephen’s College, Delhi University in 1999. He spent two more years at the University of Cambridge before starting a PhD at Yale University in 2001 where he worked on the Josephson Bifurcation Amplifier. After his postdoctoral work on Josephson Parametric Amplifiers at University of California, Berkeley, Vijay returned to India and joined TIFR to start a new laboratory. He currently heads the Quantum Measurement and Control Laboratory where the main goal is to develop techniques to stabilize quantum states against decoherence and develop small scale quantum processors.
Storing and processing information using quantum two level systems (qubits)
promises tremendous speed-up for certain computational tasks like prime factorisation and searching an unsorted database. In addition, many problems in quantum mechanics can also be solved a lot more efficiently. Scientist and engineers all over the world are trying to build the hardware that can implement these quantum algorithms. In this talk, I will present one particular approach which uses superconducting electrical circuits operating at millikelvin temperatures to implement the quantum hardware. I will introduce a new three-
qubit device, nicknamed “trimon” [1], which is based on a multi-mode superconducting circuit providing strong inter-qubit coupling. I will discuss the basic working principles of the device, the implementation of efficient multi-qubit gates and the capability of universal programmability [2]. Next, I will demonstrate the high-fidelity preparation of various two- and three-qubit entangled states and realization of a few quantum algorithms like Deutsch-Jozsa, Grover etc [3]. I will end by talking about the possibility of scaling to larger systems using the trimon as a building block and the challenges ahead.
References:
[1] Roy et al., Phys. Rev. Applied 7, 054025 (May 2017)
[2] Roy at al., arXiv:1711.01658 (Nov 2017)
[3] Roy et al., arXiv:1809.00668 (Sep 2018)
Photon propagation in nanostructured media is a topic of immense current interest. For a periodic nanostructure, the photon experiences transmission bands and bandgaps akin to electrons in conductors. The addition of disorder to the periodic template realizes an exotic mesoscopic phenomenon known as Anderson localization of photons, that arrests transport via self-interference of multiply scattered waves. So far, several features of photon transport such as diffusion, weak and strong localization etc have been well-documented, but there is not much literature on transport of hybrid quasiparticles. In this talk, we shall describe our work on Anderson localization of a hybrid quasiparticle created by the coupling of a plasmon mode with an optical resonance in a periodic system. Under disorder, localization occurs at the hybridization gap and the Anderson localized modes tend to populate the vicinity of the gap-edge. We observe that, contrary to conventional photon localization, the frequency of the localized quasiparticles is pinned to the optical resonance frequency. We shall show how this unique feature defeats much of the commonly expected behaviour of localized light.
Sushil Mujumdar completed his PhD from Raman Research Institute, Bangalore, after which he was awarded the ‘Training and Research in Italian Labs’ Fellowship by the International Center for Theoretical Physics, Trieste, to perform research at the European Laboratory for Nonlinear Spectroscopy (a European Large-scale Laser Facility) in Florence, Italy. Subsequently, he completed a postdoctoral assignment at the University of Alberta, Canada and a Research Associateship at the Laboratory of Nano-Optics, ETH, Zurich. He currently serves as Associate Professor at the Tata Institute of Fundamental Research, Mumbai, where he runs an experimental programme in “Nano-optics and Mesoscopic Optics”.
Light-matter interaction has conventionally been studied using `small’ atoms interacting with electromagnetic waves (light) of wavelength that is several orders of magnitude larger than the atomic dimensions. In contrast, here we experimentally demonstrate a vastly different regime, where an artificial atom interacts with acoustic waves (sound). Experiments where one `talks’ and `listens’ to these artificial atoms are discussed. A new regime of quantum optics — the giant atom regime — where the atoms interact with waves of wavelength several orders of magnitude smaller than the atomic dimensions is realised using a superconducting qubit coupled to surface acoustic waves (SAW) at two points with mutual separation on the order of 100 wavelengths, thereby also realising an intrinsically non-Markovian system dynamics.
Baladitya Suri obtained his B.Tech in Engineering Physics from Indian Institute of Technology Madras (IIT Madras) in 2006 and PhD in Physics from University of Maryland, College Park, USA in 2015. He was employed as a post-doctoral researcher at the Quantum Technologies Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, Gothenburg, Sweden during 2015-2018, and joined the Department of Instrumentation and Applied Physics, IISc in March 2018 as an Assistant Professor.
The device research community is currently working on diverse device architectures along with different semiconductor materials to meet ever-increasing demand for high-speed and low power VLSI circuits. Among different options, the III-V Nanowire (NW) transistors offer the highest electrostatic control, superior short-channel behaviour and excellent transport properties compared to their silicon counterpart. Several recent literatures have demonstrated the integration feasibility of III-V NW transistors. However, the ultimate production of integrated circuits (ICs) with III-V NW transistors will depend on their circuit performance, whose evaluation needs computationally efficient and accurate compact models.
The existing industry standard compact models are developed as a solution of the Poisson’s equation with quantum effects often added as correction factors. Note that the III-V multi-gate (MUG) transistors show significant quantum behaviour due to high quantum-confinement (smaller dimension) and the lower effective mass of III-V materials. Because of this, the energy bands split into sub-bands and there is a need to consider 2D or 1D Density of States (DOS) along with the Fermi-Dirac (FD) statistics. The existing models use the 3D DOS with Boltzmann approximation, therefore cannot accurately describe the effects shown by III-V MUG transistors.
In this talk, I will present, Constant Charge Density Approximation (CCDA), a simple but effective approximation which eliminates the need of using the exact form of the wave function. The said approximation significantly simplifies the calculation of the channel potential profile while maintaining the accuracy of the calculated charge density. The perturbation term is calculated analytically by using the approximation, which is then used to model the electrical confinement. The presented compact model is physics-based, facilitates the consideration of higher energy sub-bands without increasing the mathematical complexity and is free from any empirical parameter thus making it computationally efficient and suitable for circuit simulators. The model is developed for NW transistors however, the proposed approximation is general and can be used to model transistors with other geometries, thus providing a simple method to model any III-V multi-gate transistors.
The existing compact models for III-V NW transistors assume parabolic conduction band. However, in the case of III-V materials the conduction band non-parabolicity is high and cannot often be neglected. The conduction band non-parabolicity modifies the energy level and the dispersion relationship affecting the charge and capacitances. In this talk, I will also present a methodology to include the conduction band non-parabolicity in both the energy level and dispersion relation using fitting parameters. The proposed non-parabolic model when applied with CCDA, enables us to analytically derive the charge and capacitance.
Dr. Nihar Ranjan Mohapatra is currently working as an Associate Professor at IIT Gandhinagar. Prior to joining IIT Gandhinagar in July 2011, he worked in semiconductor industries like IHP Microelectronics, Advanced Micro Devices (AMD) and GLOBALFOUNDRIES for eight years. During that time he worked on CMOS technologies starting from 130nm till 28nm. In his last assignment at GLOBALFOUNDRIES, he was responsible for integrating several memory devices (SRAM, eDRAM and NVM) in 28nm bulk CMOS technologies. His current research interests are in nano-electronic devices, CMOS technology, CMOS device and process development, compact modelling, semiconductor device reliability, computational lithography and analog circuit design. He has authored and co-authored several papers on international journals and conference. He has also received research funding from several public and private organisations including Department of Science and Technology, Ministry of Electronics and Information Technology, ISRO, GLOBALFOUNDRIES etc. He is an active member of IEEE EDS, IEEE SSC and he loves to teach and interact with students.
The New Brand of Hybrid and Inorganic Halide Perovskites: The Tunable Multifaceted materials for Energy and Optoelectronics
Satishchandra Ogale
Indian Institute of Science Education Research, Dr. Homi Bhabha Road, Pune, India
satishogale@gmail.com, satishogale@iiserpune.ac.in
The new brand of organic-inorganic hybrid perovskites (OIHPs) and the inorganic halide perovskites represent a rapidly growing family of materials with exceptional, intriguing, and highly tunable device-worthy properties; especially for solar cells and other optoelectronic devices. Indeed, with the emergence and rapid growth recent research on this class of materials, the landscape of solar cells has witnessed a dramatic change over the past few years enabling very high solar conversion efficiencies >23%. The efficiency projections for some tandem architectures involving these materials (with silicon cells and other cell types) are as high as 35%. In contrast to the basic 3D versions of the hybrid perovskites which still suffer from some issues related to stability, their low dimensional counterparts have not only shown interesting and highly promising optoelectronic properties but also significantly higher stability for robust device applications. They represent ‘natural quantum well’ structures which can be tailored easily to achieve new interesting materials with novel properties. In fact, the quantum confinement effects and peculiar electronic density of state spectra in such systems have interesting consequences for emergent optoelectronic devices as well. In my talk I will outline this exciting scenario with some examples derived from own research referenced below.
Funding Support: DST-CERI, DST-Nanomission (Thematic Unit), APEX-I and II, SUNRISE
References: Angew. Chem. Int. Ed. 57, 7682, 2018, Adv. Opt. Mater 1800751, 2018, J. Phys. Chem. C, 122, 5940, 2018, ChemSusChem, 10, 3722, 2018, J. of Mater. Chem. A, 5, 18634, 2018, Adv. Mater. Interfaces, 4, 1700562, 2018, J. Appl. Phys. 121, 133107, 2017, J. Phys. Chem. Letts., 7, 4757, 2016, ACS Appl. Mater. Interfaces, 8, 854, 2016
Dr. Satishchandra Ogale is currently working at the Indian Institute of Science Education and Research (IISER) Pune as Professor Emeritus, Department of Physics and Centre for Energy Science. His field of research is Advanced Materials and Nanotechnology. More recently his research focus has been on Clean Energy harvesting, storage and conservation.
He has been first rank holder in all his School, College and University examinations starting with SSC (then 11th) when he stood first in the entire state of Maharashtra, followed by Pre-Professional, BSc and MSc Physics examinations.
He has over 480 research publications in International peer-reviewed journals including Nature, Nature Materials, Science, Energy and Environmental Science, Physical Review Letters, Advanced Materials, Angew Chem, Nano Energy etc. He has also published several review articles and edited two books for Springer and Wiley.
He is on the Editorial Advisory Boards of high impact international journals Energy and Environmental Science, Sustainable Energy and Fuels, Nature’s Scientific Reports and ACS Applied Materials and Interfaces. He has many international collaborations and has presented several Plenary/Keynote/Invited talks in National and International Conferences.
Over the years he has supervised over 65 PhD students. He spent about 10 years at the University of Maryland, College Park, as Visiting Professor and Senior Research Scientist, before returning to India in 2006 and joining National Chemical Laboratory, initially as Ramanujan Fellow and Later as Chief Scientist. Prior to that he was Professor of Physics and also Chair (1992-95), Department of Physics at Pune University.
He has won several national awards/recognitions including the INSA young scientist medal, Dr. N. S. Satyamurthy prize (IPA-DAE), B. M. Birla Prize (Birla Science Foundation), Sir C. V. Raman prize (UGC, Hari-Om trust), MRSI medal, MRSI special silver jubilee medal etc. He is also the elected fellow of the Indian Academy of Science, the National Academy of Science and the Maharashtra Academy of Science. He is also the fellow of the Royal Society of Chemistry (FRSC). Recently, a multi-institutional UK-India team was awarded the prestigious international Newton Prize (GBP 200,000) of the British Council, of which Prof. Ogale was one of the team leaders.
Perovskite solar cells (PSCs) with over 23% of power conversion efficiency (PCE) are attracting extensive interest in renewable energy to deliver low-cost electricity and to reduce carbon dioxide emission (1). However, their commercialization and practical applications are still restricted by insufficient long term stability in ambient atmosphere. Therefore, advances particularly in improving device stability without sacrificing the efficiency is vital for the future of PSCs. One of the reasons of efficiency degradation in PSCs is attributed to unstable perovskite materials itself composed of small organic cations (A+), metal cations (B2+) and halide anions (X-), which form a three-dimensional (3D) crystal structure of ABX3. To improve photostability, various cations, formamidinium (FA+), cesium (Cs+), rubidium (Rb+), and anions, bromide (Br-), and chloride (Cl-) have been explored for mixed 3D perovskites; [FA/MA]Pb[I/Br]3, [FA/Cs]Pb[I/Br]3, or [Rb/Cs/FA/MA]Pb[I/Br]3. However, these 3D perovskites are still unsatisfied for moisture and thermal stability to commercialization. In this talk we show stable perovskite devices by compositional (2) and interface engineering involving an ultra-stable 2D/3D perovskite junction (3-4).
References
1. https://www.nrel.gov/pv/assets/images/efficiency-chart-20180716.jpg
2. Jodlowski, AD; Roldan-Carmona, C ; Grancini, G; Salado, M; Ralaiarisoa, M; Ahmad, S; Koch, N ; Camacho, L; de Miguel, G ; Nazeeruddin, MK, NATURE ENERGY, 2017, 2, 972.
3. Giulia Nature Comm, 2017, Grancini, G.; Roldan-Carmona, C; Zimmermann, I ; Mosconi, E; Lee, X; Martineau, D; Narbey, S; Oswald, F; De Angelis, F; Graetzel, M; Nazeeruddin, M. K, NATURE COMMUNICATIONS, 2017, 8, 15684.
4. Cho, K. T.; Grancini, G.; Roldan-Carmona, C.; Gao, P.; Lee, Y.; Paek, S.; Nazeeruddin, M. K. Energy Environ. Sci. 2018, 11 (4), 952.
Prof. Mohammad K. Nazeeruddin current research at EPFL focuses on Perovskite and Dye Sensitized Solar Cells and Light-emitting diodes. He has published more than 595 peer-reviewed papers, ten book chapters, and inventor/co-inventor of over 90 patents. The high impact of his work has been recognized by invitations to speak at several international conferences.
Nazeeruddin has been named Thomson Reuters “Highly Cited Researcher” and one of the 19 scientists identified by Thomson Reuters as The World’s Most Influential Scientific Minds 2016 and 2017 from all scientific domains. He has appeared in the ISI listing of most cited chemists and has more than 88’000 citations with an h-index of 130. He is teaching “Functional Materials” course at EPFL, and Korea University. He was appointed as World Class University (WCU) professor and Adjunct Professor at the King Abdulaziz University, Jeddah. Elected to the European Academy of Sciences (EURASC), and Fellow of The Royal Society of Chemistry.
http://stateofinnovation.thomsonreuters.com/the-worlds-most-influential-scientific-minds-2015?utm_term=jan&utm_content=hcr-congrats&utm_campaign=12772-HCR_WMISM-27815&utm_medium=email&utm_source=Eloqua
https://clarivate.com/hcr/wp-content/uploads/2017/11/2017-Highly-Cited-Researchers-Report-1.pdf
One of the “Top 10 university researchers in SciVal topic “perovskite; solar cells; methylammonium lead”, 2014 to 2017. https://www.timeshighereducation.com/data-bites/top-universities-and-researchers-perovskite-solar-cell-research#survey-answer
Working as Scientist in DRDO
Complete paper submission
Patrick Vogt did his first education in applied electronics at the BASF (Ludwigshafen). He obtained his Bachelor and Master degree from the University of Heidelberg in theoretical physics and solid-state physics, followed by his doctorate at the Paul-Drude-Institute (Berlin) in semiconductor science and physical chemistry. He received his Ph.D. in 2017 from the Humboldt University of Berlin. He worked as a visiting scientist at the University of California (Santa Barbara), and currently researches as a post-doc at the Helmholtz-Zentrum Berlin.
His main research topics are the fundamentals in molecular beam epitaxy of III-O and IV-O semiconductors: growth mechanisms, thermodynamics, and phase formations.
Heterostructures based on layers of atomic crystals have a number of properties often unique and very different from those of their individual constituents and of their three dimensional counterparts. The combinations of such crystals in stacks can be used to design the functionalities of such heterostructures. I will show how Raman spectroscopy can be used to fingerprint such heterosctructures, and how these can be exploited in novel light emitting devices, such as single photon emitters, and tuneable light emitting diodes.
Coupling between Surface Phonon Polaritons (SPhP) in SiC and Surface Plasmon Polariton (SPP) modes in Graphene is proposed to obtain sub-wavelength confinement and localization in the IR regime. Simulation and experimental results will be presented
Dr. Hasitha C. Hasitha is a Research Scientist at the Commonwealth Scientific and Industrial Research Organisation (CSIRO) in Melbourne, Australia. After receiving his Bachelor’s (2002) and Master’s (2006) degrees in Physics, Dr. Weerasinghe completed his PhD degree at the Department of Materials Engineering of Monash University in 2011. He has then held a post-doctoral research position at the University of Melbourne for two years. His research interests focus on fabrication of flexible photovoltaic devices/modules using roll-to-roll printing and coating processes, characterisation of flexible photovoltaic devices/modules, development of barrier encapsulation, new materials on improving stability and conducting lifetime studies of photovoltaic devices.
Organic and Perovskite-based Photovoltaics on Flexible substrates: Roll-to-roll Fabrication and Encapsulation
Hasitha Weerasinghe, Doojin Vak, Dechan Angmo, Mei Gao, Andrew Scully
Commonwealth Scientific and Industrial Research Organization – CSIRO, Manufacturing, Clayton, Victoria 3168, Australia.
Email: Hasitha.Weerasinghe@csiro.au,
Website: https://www.csiro.au/en/Research/EF/Areas/Solar/Photovoltaics
Perovskite-based and Organic-based solar cells (PeSCs and OPVs) fabricated on plastic substrates are attracting worldwide attention due to advantages such as flexibility, large-scale printability, lightweight, solution processability, and potential utility for new products. These properties allow PeSCs and OPVs to be manufactured by cost-effective industrial roll-to-roll processes on flexible substrates and makes the material as a good alternative of conjugated organic materials which have been widely used in printed solar films (PSFs). In this presentation, CSIRO’s activity on the roll-to-roll production of PSFs as well as the typical roll-to-roll printing processes will be introduced and requirements of materials/processes to be used in roll-to-roll production will be addressed. CSIRO has been working on organic based PSFs for a decade and now tackling printability (roll-to-roll compatibility) of perovskites as well as other components of PeSCs. Roll-to-roll processed/compatible electrode, charge transport layers and perovskite layers [1-2] will be presented and challenges toward the manufacturing of fully printed PeSCs will be discussed. Recently, we have demonstrated roll-to-roll processed perovskite-based devices using a modified sequential deposition method. This printing-friendly sequential deposition has been used in air with slot die coating, an industrial up-scaling technique, to produce a perovskite solar cell on flexible substrates up to 11.0% PCE.
However, poor long‐term stability of PeScs and OPVs limits the future commercial application. Exposure of these devices to atmospheric oxygen and water vapour is known to cause rapid device degradation. Encapsulation using materials having ultra-low permeability to these atmospheric constituents is required to achieve sufficient operational lifetimes for commercial applications. We have found that pre-entrained moisture in the encapsulation materials, and post-encapsulation ingress of moisture/oxygen through adhesive layers and around electrical contacts are significant lifetime-limiting factors. Encapsulation architectures were developed using a variety of flexible barrier films and adhesives to address these issues, and the lifetime of encapsulated large-area (active area ~50 cm2) fully-printed OPV having efficiency >3% modules were assessed under various storage conditions. New encapsulation architectures were found to significantly enhance the durability of printed OPV modules, with results showing modules exhibiting a shelf-life of more than 5 years under ambient conditions and durability of more than 4 years under exposure to outdoor conditions [3-4]. The effect of encapsulation on improving the operational lifetime of flexible perovskite-based solar cells prepared on polymer substrates having efficiency exceeding 13% was also studied. The lifetime of the encapsulated flexible PSC devices was extended significantly compared with that of the non-encapsulated devices. Permeation testing revealed that the post-encapsulation ingress of moisture through the adhesive layers and around electrical contacts constitutes a significant lifetime-limiting factor [5].
References
[1] K. K. Sears, M. Fievez, M. Gao, H. C. Weerasinghe, C. D. Easton, and D. Vak, Solar RRL (2017) 1, 1700059.
[2] Y.-J. Heo, J.-E. Kim, H. Weerasinghe, D. Angmo, T. Qin, K. Sears, K. Hwang, Y.-S. Jung, J. Subbiah, D.J. Jones, M. Gao, D.-Y. Kim, D. Vak, Nano Energy, 41 (2017) 443-451
[3] H.C. Weerasinghe, N. Rolston, D. Vak, A.D. Scully, R.H. Dauskardt, Solar Energy Materials and Solar Cells, 152 (2016) 133-140
[4] D. Vak, H. Weerasinghe, J. Ramamurthy, J. Subbiah, M. Brown, D.J. Jones, Solar Energy Materials and Solar Cells, 149 (2016) 154-161
[5] H.C. Weerasinghe, Y. Dkhissi, A.D. Scully, R.A. Caruso, Y.-B. Cheng, Nano Energy, 18 (2015) 118-125.
Fig 1. (a) Fully-printed 10cm × 10cm size OPV module, (b) Schematic diagram of printing-friendly sequential slot die coating of a perovskite layer
Fig 2. (a) Roll-to-roll slot die coating of Perovskite and (b) roll-to-roll coating of organic photo-active layer. (C)Fully-printed 30cm-wide organic PSFs produced at CSIRO.
Philip Feng is currently the Theodore L. & Dana J. Schroeder Associate Professor in Electrical Engineering & Computer Science at the Case School of Engineering, Case Western Reserve University (CWRU), Cleveland, Ohio, USA. His group’s research is primarily focused on emerging semiconductor devices and integrated microsystems. He received his Ph.D. in EE from California Institute of Technology (Caltech), Pasadena, CA, USA. Feng was one of the 81 young engineers selected to participate in the National Academy of Engineering (NAE) 2013 U.S. Frontier of Engineering (USFOE) Symposium. Subsequently, he was selected to receive the NAE Grainger Foundation Frontiers of Engineering (FOE) Award in 2014. His recent awards include National Science Foundation CAREER Award, 4 Best Paper Awards (with his advisees, at IEEE and American Vacuum Society conferences), and a university-wide T. Keith Glennan Fellowship. He is also the recipient of the Case School of Engineering Graduate Teaching Award (2014) and the Case School of Engineering Research Award (2015). A Senior Member of IEEE, he has served on the Technical Program Committees (TPC) and as Track/Session Chairs for IEEE IEDM, IEEE MEMS, Transducers, IEEE IFCS, IEEE SENSORS, IEEE NANO, etc. He has also served as the Technical Program Chair for the MEMS/NEMS Technical Group at The 61st to 63rd American Vacuum Society (AVS) International Symposium & Exhibition.
Atomically thin crystals have rapidly emerged to enable two-dimensional (2D) nanostructures with unusual electronic, optical, mechanical, and thermal properties. Beyond graphene, the forerunner and hallmark of 2D crystals, new elemental and compound 2D semiconductors, high-k dielectric crystals, and their van der Waals heterostructures also offer wide spectra of fascinating attributes. This presentation will focus on reporting and updating some latest highlights on exploring device physics and engineering of nanoelectromechanical systems (NEMS) based upon suspended, mechanically active atomic layer semiconductors and their vertically stacked heterostructures, toward realizing ultrasensitive transducers and ultralow-power signal processing devices at radio frequencies (RF).
We will describe 2D NEMS using atomic layer transition metal dichalcogenides (TMDCs) and black phosphorus crystals, and their van der Waals heterostructures with graphene and hexagonal boron nitride (h-BN). We have demonstrated highly electrically tunable multimode 2D NEMS resonators, featuring operating frequencies to >150MHz, and extraordinary tuning ranges up to >300% and higher, and deterministically measured dynamic range, DR~70 to 100dB and even broader, with high-precision calibration of device intrinsic noise floor and onset of nonlinearity. Ongoing studies are focused on engineering the broad DR and remarkable tunability of these atomic layer 2D NEMS, towards new functions and controls in 2D nanosystems.
Integrated GHz ultrasonics on planar systems such as CMOS chips are enabled by integration of fast, deep sub-micron transistors and GHz thin film piezoelectric transducers. Sonic wavelengths on the order of a few microns can generate wave packets with spatial extent that is less than the substrate thickness. The role of diffraction of wave packets, coupled with time-of flight have been used to form a useful set of devices. With integration with deeply scaled CMOS that provides GHz electronics, one can envision chip-scale microsystems that provide unprecedented manipulation of sonic energy. We have used these CMOS chips to demonstrate sensing biological ultrasonic impedance to extract fingerprints and tissue type, communicate on a chip using ultrasonic pulses, and implemented ultrasonic memory.
Amit Lal is the Robert M. Scharf 1977 Professor in the School of Electrical and Computer Engineering at Cornell University, Ithaca, NY. He received his B.S. degree (1990) in Electrical Engineering from the California Institute of Technology, and his Ph.D. degree (1996) in Electrical Engineering from the University of California, Berkeley. His technical interests and activities are in the areas of MEMS, ultrasonics, optics, micromachining, piezoelectric systems, design and analysis of integrated circuits, and applications of radioactivity in microsystems. From 2005-2009, Prof. Lal served as a Program Manager in the Microsystems Technology Office of the Defense Advanced Research Projects Agency (DARPA), where he developed and managed programs in the areas of navigation, low-energy computation, bio-robotics, and atomic microsystems. He holds ~33 patents and has published more than 185 research papers in the area of microsystem engineering. He is the recipient of the NSF CAREER, and Whitaker Foundation award. With his students, several best paper awards at the IEEE Ultrasonics and Frequency Control Symposium and MEMS conferences.
Junichiro Kono is a leader in optical studies of condensed matter systems and photonic applications of nanosystems, including semiconductor nanostructures and carbon-based nanomaterials. He has made a number of pioneering contributions to the diverse fields of semiconductor optics, terahertz spectroscopy and devices, ultrafast and quantum optics, and condensed matter physics. Professor Kono received his B.S. and M.S. degrees in applied physics from the University of Tokyo in 1990 and 1992, respectively, and completed his Ph.D. in physics from the State University of New York at Buffalo in 1995. He was a postdoctoral research associate at the University of California, Santa Barbara, in 1995-1997 and the W. W. Hansen Experimental Physics Laboratory Fellow in the Department of Physics at Stanford University in 1997-2000. Professor Kono joined the Department of Electrical & Computer Engineering of Rice University in 2000. He is currently a Professor in the Departments of Electrical & Computer Engineering, Physics & Astronomy, and Materials Science & NanoEngineering at Rice University. Professor Kono was a recipient of the National Science Foundation CAREER Award in 2002 and has been a Fellow of the American Physical Society (APS) since 2009 and a Fellow of the Optical Society (OSA) since 2015. Professor Kono is also the founder of the nationally recognized international program for science and engineering undergraduate students, NanoJapan, funded by the U.S. National Science Foundation, receiving the Heiskell Award for Innovation from the Institute of International Education in 2008.
The diverse applications of terahertz (THz) radiation and its importance to fundamental condensed matter science makes finding ways to generate, manipulate, and detect THz radiation one of the key areas of modern applied physics. However, despite decades of worldwide efforts, the THz region of the electromagnetic spectrum still continues to be elusive for solid-state technology. Recently, there has been a growing recognition that carbon nanomaterials – i.e., graphene and carbon nanotubes (CNTs) – have some outstanding electronic and photonic properties that are ideally suited for THz devices. In this talk, after reviewing the past, current, and future of the THz science and technology of graphene and carbon nanotubes, we will present some of our latest results on THz dynamic conductivity and ultrafast carrier dynamic as well as THz devices including polarizers, modulators, and detectors.
Saikat Guha is an Associate Professor of Optical Sciences at the University of Arizona. He earned his B.Tech. degree in electrical engineering in 2002 from the Indian Institute of Technology Kanpur (India), followed by S.M. and Ph.D. degrees in 2004 and 2008 respectively, from the department of electrical engineering and computer science at the Massachusetts Institute of Technology. He was with the Quantum Information Processing group at Raytheon BBN Technologies, in Cambridge MA, from 2008 to 2017, where in his most recent role as Lead Scientist, led several sponsored projects in topics revolving quantum enhancements in photonic information processing. His research interests span quantum limits to optical communication and sensing, optical quantum computing, and network information theory. Guha represented India at the International Physics Olympiad in 1998, where he was awarded the European Physical Society award for the experimental component. He was a co-recipient an honorable mention in US National Security Agency’s best paper in cybersecurity award for his work on quantum secured covert communications. His Defense Advanced Research Projects Agency Information in a Photon team won the Raytheon 2011 Excellence in Engineering and Technology Award, Raytheon’s highest technical honor, for outstanding research on fundamental limits of optical communication. is an Associate Professor of Optical Sciences at the University of Arizona. He earned his B.Tech. degree in electrical engineering in 2002 from the Indian Institute of Technology Kanpur (India), followed by S.M. and Ph.D. degrees in 2004 and 2008 respectively, from the department of electrical engineering and computer science at the Massachusetts Institute of Technology. He was with the Quantum Information Processing group at Raytheon BBN Technologies, in Cambridge MA, from 2008 to 2017, where in his most recent role as Lead Scientist, led several sponsored projects in topics revolving quantum enhancements in photonic information processing. His research interests span quantum limits to optical communication and sensing, optical quantum computing, and network information theory. Guha represented India at the International Physics Olympiad in 1998, where he was awarded the European Physical Society award for the experimental component. He was a co-recipient an honorable mention in US National Security Agency’s best paper in cybersecurity award for his work on quantum secured covert communications. His Defense Advanced Research Projects Agency Information in a Photon team won the Raytheon 2011 Excellence in Engineering and Technology Award, Raytheon’s highest technical honor, for outstanding research on fundamental limits of optical communication.
In the cluster model of quantum computing, any quantum algorithm can be implemented by an adaptive sequence of measurements at the nodes of a graph, where the nodes are qubits (photons in our case) and edges between two nodes represent entanglement. An entangled cluster in a 2D square lattice topology is known to a resource for universal quantum computing. Photons are a promising candidate for encoding qubits scalably but assembling a large photonic entangled cluster state (using photons and linear optical circuits) is a challenge, since each step relies on probabilistic operations, and losses in transmission and detection. I will describe a new proposal for cluster-model photonic quantum computing that combines ideas from recent work on “boosted” linear optics based Bell basis measurements, percolation theory and quantum error correction for photon loss. In this architecture, small photonic clusters are fused in an efficient “ballistic” fashion, i.e., without any detection-induced feedback, into a long sheet of entangled photons, which can then be re-cast into a logical square-lattice graph for quantum computing. Aside from the obvious uses in general-purpose quantum computing, I will also talk about applications of photonic cluster states to a special purpose quantum processor known as quantum repeater, which will be a key enabler to a future quantum internet.
Professor Srinivasan Anand is at the Department of Applied Physics, School of Engineering Sciences, KTH Royal Institute of Technology, Stockholm, Sweden. He has over 25 years of experience in the field of semiconductors including nanostructures and nano-structured materials. His current research focuses on semiconductor nanostructures and aims to fundamentally advance nanophotonic and electronic device physics, nano-fabrication and materials technologies for optical and optoelectronic components. His expertise and research interests include point defects in III-V materials; Photonic semiconductor nanostructures including photonic crystals and metasurfaces and their applications in photovoltaics, light emitting devices, optical sensing, photo-detectors and non-linear optics; Nanofabrication methods: low-cost approaches, self-assembly, Ion-beam etching techniques; and Scanning probe based high resolution characterization techniques. In these fields he has authored or co-authored over 230 journal publications (115) and conference contributions (papers/abstracts); he has given several invited talks at international conferences; he is a co-inventor on three patents (13 filings).
Dielectric metasurfaces, by appropriate choice of their geometrical and material properties, can offer new or added light manipulation functionalities in surface optical coatings and also at optical interfaces in optoelectronic devices. We present our recent research on semiconductor nanostructure based meta-surfaces focusing on their optical properties, fabrication technologies and selected application examples. Ion-bombardment assisted self-organization phenomenon is investigated and used to generate spatially disordered assemblies of sub-wavelength InP-based nanodisk/nanopillars. Depending on their geometrical dimensions, these meta-surfaces provide interesting properties such as structural colors and broad-band anti-reflection. The latter feature is utilized to demonstrate a InP-nanopillar based conformal pn junction solar cell. Using a combination of colloidal lithography and etching techniques a-Si nanodisk array based meta-surfaces were fabricated. The refractive indices of the substrate and the surrounding matrix are shown to dramatically influence the transmittance and reflectance spectra from the a-Si nanodisk metasurfaces. These properties are utilized to realize broad-band antireflection for PV applications as well as spectral filtering in reflection and transmission modes. Finally, a novel add-on surface nanostructuring method by which sub-wavelength nanoparticles from solution phase are packed together into pre-designed patterns and geometrical shapes is presented. This method not only combines the advantages of top-down and bottoms-up approaches, but also provides unique possibilities to combine materials and to form surface structures on arbitrary substrate materials including pre-fabricated device surfaces. As an example, we demonstrate micro and nano patterns directly added-on to different substrates and device surfaces by compacting titania nanoparticles using pre-formed soft silicone molds. Proof of concept application examples include validation of add-on structured surface coatings on pre-fabricated GaN based LEDs for efficient light extraction and on pre-fabricated planar single junction solar cells (Si, GaAs and InP) for broad-band antireflection.
Amitava Das did his Ph.D. in EE from Purdue University in 1990 under guidance of Prof. Mark Lundstrom. He worked in various roles during his 25+ years in the semiconductor industry – first as a faculty of EE at IIT-B, then developed 0.18um CMOS technology at APRDL, Motorola, worked as an RF IC/Module Design Lead in Motorola’s wireless IC design division. Amitava moved to operations role at Motorola productizing very high-volume IC’s with a global supply chain. Amitava co-founded Tagore Technology with Manish Shah in Mar, 2011. Tagore Technology is a venture funded fabless GaN IC company. Amitava has more than 30 papers and patents.
Advantages of GaN technology in the area of RF and Power Electronics are well documented. This talk will address the next phase of the evolution – technical and economic challenges that we face while displacing the incumbent technology, Si, especially in the area of industrial and consumer applications.
Application of GaN in the area of RF is more widespread than in power electronics applications. Besides power amplifiers, Tagore Technology has developed very compact high power RF switches for various infrastructure applications. We will discuss GaN products/applications in the context of wideband radio’s, such as SDR as well as narrow band applications such as in 5G small cells.
GaN on Si technology is emerging as a strong contender for power electronics applications in the mid voltage range (100-650V). Unlike RF, GaN is just beginning to appear in power applications. Tagore Technology has developed GaN half bridge with integrated driver to ease design of GaN into various power applications. We will highlight a few areas where we see GaN to play an important role in the near term (1-3 years).
2004. Ph. D. Seoul National University
2004-2007 Post Doc. UC Berkeley
2007-2008 Assistant Prof. Konkuk Univ. Seoul, Korea
2008-Present, Professor, Korea Institute for Advanced Study, Seoul, Korea
In this talk, I will review my recent studies on critical effects of interlayer interaction on determining electronic and structural properties of layered two dimensional crystals. It is shown that the structural stabilities, electronic energy bands as well as topological properties are critically dependent of nature of interlayer interaction between adjacent two-dimensional crystals. Examples include twisted bilayer graphene [1], 1T’-type transition metal dichalcogenides [2] and strained bilayer crystals [3].
[1] S. J. Ahn et al, Science 361, 782 (2018).
[2] H. J. Kim et al, Phys. Rev. Rapid. Comm. 95, 180101 (2017).
[3] J. Lee et al, Nature Communication 8, 1370 (2017).
Hiroshi YAMAGUCHI received his B.S., M.S. in physics and Ph.D. degrees in engineering from Osaka University in 1984, 1986, and 1993, respectively. He joined NTT Basic Research Laboratories, Nippon Telegraph and Telephone Corporation in 1986 and has been engaged in the study of compound semiconductor surfaces using electron diffraction and scanning tunneling microscopy. His current interests are micro/nanomechanical devices using semiconductor heterostructures. He is currently an executive manager of Quantum and Nano Device Research and a group leader of Nanomechanics Research Group.
The manipulation of acoustic waves is the focus of much attention in various applications from high-frequency signal processing to quantum information technologies. We develop one-dimensional phononic crystal waveguides using the architecture of GaAs/AlGaAs-based microelectromechanical resonators [1]. This novel kind of devices can artificially design the dispersion relationship of acoustic waves and also electrically control their propagation using nonlinear elastic response of the suspended structures. In this invited talk, we will review our recent activities, including the results on phonon transistors and random access memories [2,3], dynamical control of acoustic wave propagation [4], and temporal focusing of acoustic waves [5].
[1] H. Yamaguchi, Semicond. Sci. Technol. 32, 103003 (2017).
[2] D. Hatanaka, I. Mahboob, K. Onomitsu, and H. Yamaguchi, Appl. Phys. Lett. 102, 213102 (2013).
[3] D. Hatanaka, I. Mahboob, K. Onomitsu, and H. Yamaguchi, Appl. Phys. Express 7, 125201 (2014)
[4] D. Hatanaka, I. Mahboob, K. Onomitsu, and H. Yamaguchi, Nature Nanotechnol. 9, 520 (2014).
[5] M. Kurosu, D. Hatanaka, K. Onomitsu, and H. Yamaguchi, Nature Commun. 9, 1331 (2018).
Since 2004 Horst Hahn is Executive Director of the Institute of Nanotechnology at Karlsruhe Institute of Technology (KIT) in Germany. His research is in fundamentals of nanostructured materials and their application in various fields, ranging from printed electronics to catalysis. Horst is principal investigator at the Herbert Gleiter Institute of Nanoscience in Nanjing, China. Previously, Horst was Full Professor of Materials Science at Technische Universität Darmstadt from 1992 to 2018, and Associate Professor at Rutgers University in New Jersey, USA, from 1990 to 1992. From 2011 to 2016 Horst was Founding Director of the Helmholtz Institute Ulm for Electrochemical Energy Storage (HIU), a joint institute between KIT and Universität Ulm. Horst is member of the German Academy of Sciences, Leopoldina, the European Academy of Sciences and the US National Academy of Engineering. Horst has publsihed more than 350 peer-reviewed papers and holds 10 patents. He has received several awards, including the Heyn Denkmünze by the German Materials Society and the Robert Mehl Medal of TMS, US.
The use of inorganic seminconductors for printed electronics offers a range of advantages compared to inorganic semiconductors, for example environmental stability and high field effect mobility. However, several problems such as need high temperature processing have prevented their wide-range use in printed applications. Using electrolyte gating, it has been demonstrated the oxide semiconductors in the form of nanoparticulate dispersions can be implemented into field effect transistors (FET) with field effect mobilities of up to 15 cm2/Vs, even if processed at room temperature. Processing at elevated temperatures, it has been demonstrated that the field effect mobility can reach the intrinic value of the material. The novel concept of an electrolyte gated vertical FET (V-FET) yield high current densities. Several FET have been integrated in small devices, such as ring oxcillators, to demonstrate the capability of integration and to examine the performance of the devices.
Dr. Tapas Dutta received the Ph.D. degree in nanoelectronics from INP Grenoble, France in 2014. During 2014-17, he was with IIT Kanpur, India as a post-doctoral researcher where his work was focused on multi-scale simulations of III-V and 2D material based transistors, modeling and circuit applications of negative capacitance transistors, and the industry standard BSIM-SOI compact model. He is currently with the university of Glasgow as a research associate working on TCAD tool development and the EU project SUPERAID7. He is also with Semiwise Ltd, working on a new variability resistant CMOS technology geared towards IoT and AI applications.
Negative capacitance based field effect transistors (NCFETs) have been demonstrated to achieve sub-60 mV/dec subthreshold swing and high drive currents. Consequently, they are being pursued as a means to enable supply voltage scaling and superior performance for different device architectures and technology nodes. In this talk, I will present the impact of statistical variability in ferroelectric based NCFETs, focusing on random dopant fluctuations and gate line edge roughness acting separately and simultaneously. In order to simulate the NCFETs, we couple a 3D transistor simulator well suited for statistical variability simulations, with the Landau-Khalatnikov model of the ferroelectric. I will also discuss the impact of device scaling and the existence of a trade-off between variability suppression due to NC effect and the ferroelectric layer’s own contribution to the total variability.
III-O compounds are a new class of materials that are currently enjoying great attention in the field of semiconductor technology. Gallium oxide (Ga2O3) is the archetypal example for its ability to handle extremely high voltages and its optical transparency in the deep ultraviolet region. Such components are based on very thin, ultrapure semiconductor layers produced by special deposition methods, such as molecular beam epitaxy (MBE).
This talk presents a marked increase in yield of Ga2O3 by a catalytic effect observed for the first time during physical vapor deposition – designated as metal-exchange catalysis. The underlying MBE studies (by which this effect was revealed) show that by adding the element In to the Ga-O system, a drastic enhancement in the growth rate of Ga2O3 occurs. In the presence of In, Ga2O3 still forms under conditions in which it could never form without the added element. Consequently, Ga2O3 crystallizes into a special hexagonal modification that is uniquely suitable for developing novel Ga2O3-based devices.
Given the simple reaction chemistry of MBE: the presented metal-exchange catalysis is expected to be general and applicable to all materials possessing similar properties to those of the investigated Ga2O3 – opening a new path for the MBE of future electronics.
Piran R Kidambi, Assistant Professor, Vanderbilt University
Atomically thin 2D materials have been extensively researched for electronic application and synthesis efforts has focused on minimizing defects and obtaining larger single crystals. However, 2D materials offer transformative opportunities as ultra-thin barriers and membranes for molecular separations. Pristine graphene and h-BN are impermeable to species larger than protons but the introduction of nanoscale defects in the 2D material lattice allows for the creation of size-selective nanoporous atomically thin membranes.
Here, I will discuss advances in 2D material synthesis and integration/processing routes to realize i) large-area atomically thin gas barriers, ii) fully functional nanoporous atomically thin membranes for dialysis based molecular separations, iii) novel approaches for in-situ growth of nanopores in 2D materials, and iv) the development of methods to probe sub-nanometer to nanometer defects over centimeter scale single crystalline 2D materials. Specifically, I will focus on the role of defects and associated engineering challenges with quality and scalability for electronics vs membrane applications.
References
Kidambi P.R. et al. Adv. Mat. 2018
Prozorovska L. and Kidambi P.R. Adv. Mat. 2018
Kidambi P.R. et al. ACS App. Mat. & Int. 2017
Kidambi P.R. et al. Adv. Mat. 2017
Kidambi P.R. et al. Adv. Mat. 2017
Kidambi P.R. et al. Nanoscale 2017
Kidambi P.R. et al. Chem. Mat. 2014
Kidambi P.R. et al. Nano Letters 2013
Two dimensional magnetic materials, with tunable electronic properties could lead to new spin- tronic, magnetic and magneto-optic applications. Here, we explore intrinsic magnetic ordering in two dimensional monolayers of transition metal tri-halides (MX3, M = V, Cr, Mn, Fe and Ni, and X = F, Cl, Br and I), using density functional theory. We find that other than FeX3 family which has an anti-ferromagnetic ground state, rest of the trihalides are ferromagnetic. Amongst these the VX3 and NiX3 family are found to have the highest magnetic transition temperature, beyond the room temperature. In terms of electronic properties, the tri-halides of Mn and Ni are either metals or Dirac half metals, while the tri-halides of V, Fe and Cr are insulators. Among all the tri-halides studied in this paper, we find the existence of very clean spin polarized Dirac half metallic state in MnF3, MnCl3, MnBr3, NiF3 and NiCl3. These spin polarized Dirac half metals will be immensely useful for spin-current generation and other spintronic applications.
Wide bandgap (WBG) semiconductors have provided stable solutions to problems created by limitations in Si technology especially for high power and high temperature segments in power electronics [1]. Compared to silicon, WBG materials have better conduction and switching properties, enabling smaller, faster and more efficient devices with higher temperature and voltage tolerances. In addition to these, WBG devices have higher durability and reliability, which help push boundaries of today’s emerging applications like hybrid electric vehicles and renewable energy generation and storage.
To design and optimize these WBG based heterojunction device structures, there is a need for structural and compositional characterization at subnanometer scale. Atom probe tomography (APT) is a powerful technique to analyze materials at the nanoscale. This lensless point-projection microscopy technique resolves individual atoms from a nano-dimensional tip with magnifications up to 106. The continuous removal of atoms provides the ability for 3D elemental characterization of the solid along with chemical distributions, grain boundary segregation, nature of interfaces, dopant distributions, etc.
In this presentation, I will focus on Ga-based device structures particularly High Electron Mobility Transistors (HEMTs) and the contribution of APT to its development. HEMT’s are vital high-power modules for communication systems based on WBG technology. The performance and quality of these heterojunction devices relies on the interfacial integrity, homogeneity, dopant distributions, and composition of the active layers. APT was used to provide important compositional information to improve device fabrication and to correlate electronic properties with materials properties. Various complex and diversified physical phenomena (e.g., Ga incorporation within the inter-layers of the HEMT, randomization of the In within InGaN LEDs, etc.) were observed and elucidated during this study [2-3].
Reference
1. J. Millán, P. Godignon, X. Perpiñà, A. Pérez-Tomás and J. Rebollo, IEEE Transactions on Power Electronics 29, (2014) 2155.
2. B. Mazumder, S.W. Kaun, J. Lu, S. Keller, U.K. Mishra and J.S. Speck, Appl Phy Lett 102, (2013) 111603
3. D. A. Browne, B. Mazumder, Y. Wu, and J. S. Speck, Journal of Applied Physics, 117 (2015) 185703
Baishakhi Mazumder is an Assistant professor at the Department of Materials Design and Innovation, University at Buffalo (UB) USA. Her research interest lies in the structure-property correlation of semiconductor systems using Atom Probe Tomography (APT). Dr. Mazumder’s work in determining critical material properties using APT has contributed in the growth of next generation communication and power electronics devices. She has collaborated with researchers worldwide in several avenues of APT, particularly in investigative research of novel materials and structures. She received her PhD in Material Science from the University of Rouen, France on understanding physical phenomenon of poor conducting materials during field evaporation. Prior to UB, she has worked as a senior material scientist at Intel Corporation and as a research associate at Oak Ridge National Laboratory. She serves as a member to various scientific societies, is a reviewer of prestigious journals and part of Science Technology Engineering and Math (STEM) activities at UB.
Two-dimensional (2D) materials, like graphene and transition metal dichalcogenides (TMDs), and their heterostructures are becoming materials of the century for possible applications in future technologies owing to their large surface area, layer dependent properties, and sustenance of inherent physical properties at small scale. Under the shadow of some wide open problems for process integration, 2D materials have come a long way and will keep continuing the same in combination with existing three-dimensional (3D) semiconductors like silicon by forming 2D/3D hybrid devices.
Here, the case of the most intensively studied simple heterostructure of graphene and silicon (G/Si), representing a rectifying interface, will be presented. G/Si structures are studied for their potential optoelectronic applications as photodiodes, where graphene acts as a transparent conductive electrode. We find that insulating regions in G/Si based devices, fabricated using back-end-of-line technology, significantly contribute towards the photocurrent in such structures. Having identified the fundamental origins of photocurrent in G/Si structures using scanning photocurrent microscopy, we optimally design the device structure to enhance their responsivity and quantum efficiency, which exceeds that of commercially available Si photodiodes. The study brings forth the importance of device design which can be easily integrated in conventional semiconductor technology, given the availability of large-area CVD graphene, without adopting complex design structures. The design approach can further can be extended to other 2D-2D and 2D-3D hybrid devices.
Dr. Satender Kataria received his Ph. Degree from University of Madras, India, in 2010. Currently, he is with Chair of Electronics Devices, RWTH Aachen University, Germany. His current research interests are large-area synthesis and applications of 2D materials and their heterostructures.
Advantages of GaN technology in the area of RF and Power Electronics are well documented. This talk will address the next phase of the evolution – technical and economic challenges that we face while displacing the incumbent technology, Si, especially in the area of industrial and consumer applications.
Application of GaN in the area of RF is more widespread than in power electronics applications. Besides power amplifiers, Tagore Technology has developed very compact high power RF switches for various infrastructure applications. We will discuss GaN products/applications in the context of wideband radio’s, such as SDR as well as narrow band applications such as in 5G small cells.
GaN on Si technology is emerging as a strong contender for power electronics applications in the mid voltage range (100-650V). Unlike RF, GaN is just beginning to appear in power applications. Tagore Technology has developed GaN half bridge with integrated driver to ease design of GaN into various power applications. We will highlight a few areas where we see GaN to play an important role in the near term (1-3 years).
Amitava Das did his Ph.D. in EE from Purdue University in 1990 under guidance of Prof. Mark Lundstrom. He worked in various roles during his 25+ years in the semiconductor industry – first as a faculty of EE at IIT-B, then developed 0.18um CMOS technology at APRDL, Motorola, worked as an RF IC/Module Design Lead in Motorola’s wireless IC design division. Amitava moved to operations role at Motorola productizing very high-volume IC’s with a global supply chain. Amitava co-founded Tagore Technology with Manish Shah in Mar, 2011. Tagore Technology is a venture funded fabless GaN IC company. Amitava has more than 30 papers and patents.
Monolayers of transition metal dichalcogenides (MX2, M=Mo,W) are found to have their valence band maximum at K point. In most instances when the second layer is added, the interaction between the two layers results in the valence band maximum shifting to Gamma. As the valence band maximum at K point is contributed primarily by dxy and dx2-y2 orbitals of the transition metal atom, one finds that spin-orbit interactions lead to large spin splittings of the valence band maximum. This has interesting consequences as spin-orbit interactions alone cannot lead to magnetic order. This then implies that the spin splitting at the symmetry point -K is opposite in direction to that at K. In this talk I will present our recent results of how the spin splittings evolve for bilayers of MoSe2 .
This is work done in collaboration with Poonam Kumari and Joydeep Chatterjee.
Priya Mahadevan is a Senior Professor at the S.N.Bose National Centre for Basic Sciences, Kolkata. Her research interests include understanding electronic, magnetic, structural and optical properties of materials using a combination of ab-initio and model Hamiltonian methods.
Kerr micro-resonator based frequency comb has paved the way for the generation of mode-locked cavity soliton (CS) on chip. These CS belongs to a class of dissipative solitons which are stable temporally confined optical pulses and corresponds to a broad frequency comb (FC), where the frequency lines are separated one cavity free spectral range (FSR) apart. A CW pump is employed to generate the CS from vacuum fluctuations in a high Q cavity by transitioning through Modulational instability and chaotic regime, which is realized by making adjustments to the detuning and the pump power. Although, CW driven Kerr FC has been widely used for these applications, researchers are now looking at different configurations for more versatility, flexibility and application specific benefits. Among these are endeavors dedicated to dual micro-resonator/ dual cavity-based FC for dual-spectroscopy, coupled micro-resonator based FC for improving efficiency in FC generation, FC generation in micro-resonators possessing simultaneous second order and third order nonlinearity for locking the carrier envelope offset frequency. Deploying two pumps instead of a single CW input is another interesting dimension to explore. These schemes may include two separate input laser sources, or a single laser source being modulated by an external modulator. Consequently, we can access a whole new regime and tweaking parameters including equal/unequal detuning, equal/ unequal pump power, modulation frequency between the two pumps and so on. In this talk, I shall present the benefits of dual-pump Kerr micro-resonator in temporal domain behavior, with an application to realize synchronous optical buffer [1]. Also, I shall discuss an analytical model to predict the onset of modulation instability in dual-pump microresonators which can be used to identify distinct regimes of operations [2].
[1] A. Roy, R. Halder and S.K. Varshney, “Robust, Synchronous Optical Buffer and Logic Operation in Dual-pump Kerr Micro-Resonator,” IEEE J. Lightwave Technology (2018), In Press
[2] A. Roy, R. Halder and S.K. Varshney, “Analytical Model of Dual-Pumped Kerr
Micro-Resonators for Variable Free Spectral Range and Composite Frequency Comb Generation,” IEEE J. Lightwave Technology, vol. 36, pp. 2422-2429 (2018).
Dr. Varshney received the M.Sc. degree in physics from Aligarh Muslim University, Aligarh, India, in 1999 and the Ph.D. degree in applied physics (on photonic crystal fibers) from University of Delhi, Delhi, India, in 2005.
In November 2008, he joined the Department of Electronics & Electrical Communication Engineering and the Department of Physics, Indian Institute of Technology (IIT), Kharagpur, India, where he is currently an Associate Professor in the Dept. of E&ECE. He is an associate faculty of School of Nanoscience and Nanotechnology, School of Energy Science and Engineering of IIT Kharagpur. He was an adjunct faculty of School of Electrical Sciences of IIT Bhubaneswar during autumn 2016 and 2017.
He was a Monbukagakusho Research Scholar (October 2002–March 2004), Postdoctoral fellow on Center of Excellence project (August 2004–March 2007), and Postdoctoral Researcher on the Japan Society for Promotion of Science (JSPS) fellowship for foreign researchers between April 2007 and November 2008 at Hokkaido University, Sapporo, Japan. He is the recipient of several fellowships-UGC/CSIR JRF fellowship from the Government of India (2000–2002), the Monbukagakusho scholarship from the Government of Japan (October 2002–March 2004), the JSPS fellowship (April 2007–November 2008), and the Alexander von Humboldt fellowship from Germany (2009), DAAD fellow (2015).
He is the author and co-author of more than 55 research papers in peer-reviewed journals and more than 80 papers in conference proceedings. His research interests include photonic components and devices, application specific specialty fibers, nonlinear photonics, quantum photonics, and optical wireless communication. He is a senior member of the Institute of Electrical and Electronics Engineers (IEEE) USA and Senior Member of Optical Society of America (OSA). He was the faculty advisor for the OSA’s student chapter at IIT Kharagpur from 2013-2015. He is currently serving as a traveling lecturer under OSA and Vice-Chair of IEEE Kharagpur Section.
Ion-conduction oxide ceramic materials are the class of materials that show high ionic conductivity even at room temperature. These materials are commonly found in 1 D olivine structure, 2D layer structure or in 3D spinal structure through which mobile Li or Na ion can move freely. Because of having its Li+/Na+ ion conductivity these materials are widely used for different technological application including solid state electrolyte. Instead of having high ion conductivity, these materials are electronically very insulating. These combined high ion conductivity and low electronics conductivity properties enable these materials to achieve at very high dielectric constant () with low loss factor that can serve as gate dielectric for low operating voltage TFT. Additionally, these ion-conducting oxide materials can synthesize by low cost, environment friendly solution processed technique. Using these dielectric, solution processed TFT can works even at 1.0 V operating voltage with reasonably high carrier mobility and on/off ratio. Moreover, with these wide band gap dielectrics, it is also possible to fabricate low power consuming optically transparent TFT that can be utilized for different optoelectronics application.
Research area: Thin film, Nanocrystal quantum dot, Sol-gel oxide, Electronics and optoelectronics device
Educational:
PhD: Indian Association for the Cultivation of Science (Jadavpur University)
BSc. & MSc: University of Calcutta (Physics)
Experience:
Current position: Assistant Professor, IIT(BHU)
Earlier experience:
Post doc, Johns Hopkins University (USA)
Post doc, Los Alamos National Laboratory (USA)
Post doc, University of Queensland (Australia)
Electromagnetic Wave frequency band lying in the range of 0.1 THz to 10 THz frequencies is defined as the THz band. High power sources and sensitive detectors development work is being carried out in this frequency range due to its potential spectroscopic application in the fields of security, military, biochemical, biomedical, communication and science. Photoconductive emitters (PCE) or Photoconductive Antennas (PCAs) are an excellent source for high power THz generation and detection. In these devices, photoexcited carriers are accelerated in the presence of an external applied electric field. This is achieved by exciting a PCE or PCA by a femtosecond laser to generate single cycle THz pulses. Using two continuous wave (CW) tunable optical wavelength range laser sources can be used as photomixing source to generate CW THz waves. We irradiated SI-GaAs substrates with high energetic carbon (C12) ions up to ~ 2μm depth such that we had uniform distribution of defects. Irradiation generates defects leading to a reduction in their carrier lifetime and an increase in the resistivity. Using these substrates, we studied pulsed as well as CW THz emission ability of irradiated material by fabricating photoconductive and photomixing emitters. The results were compared with PCAs/PCEs made of non-irradiated SI-GaAs. These can be also used as a THz detector devices.
We also studied GaN based THz sources. GaN has intrinsic defects. These defects trap and remove carriers as early as possible after femtosecond laser pulse excitation. These should give rise to high THz emission for relatively very low power. The GaN based PCA devices uses excitation in the wavelength range of ~340-370nm due to bandgap of GaN. The devices were studied at room temperature for THz emission. We will present latest results of these studies as well.
PhD in Physics from TIFR. Post-Doc from Emory University, USA. Currently Associate Professor of Physics. He has more than 45 papers in international journals, and several articles (popular and technical) in many magazines and more than 70 papers in conferences and has given several invited talks. He has THz spectroscopy and tehcnology related acitivity first time in India.
Optical beams of different spatial structures have attracted a great deal of interest due to their variety of applications in science and technology including atomic physics, plasma physics, trapping, micromachining, lithography, and high resolution microscopy. Typically, such optical beams are generated through the spatial modulation of Gaussian beams. In this talk, I will describe our recent results on high power parametric sources producing different structured beams including vortex beams, hollow Gaussian beams and Airy beams. The talk will also include some background on the origin of nonlinear optical effects, and the basics of the structured beams.
Dr. Goutam K Samanta has received B.Tech and M.Tech degree in Optics and Optoelectronics from the University of Calcutta in 2002 and 2004 and PhD in the field of Photonics from The Institute of Photonics Sciences (ICFO), Barcelona, Spain in July 2009. He joined Physical Research Laboratory, India in October 2010. His research interest includes structured laser beams, nonlinear generation of structure beams, optical parametric oscillators, and development of entangled photon source with high brightness. He has more than 120 technical contributions in peer-reviewed journals and conference proceedings along with a post deadline paper in CLEO 2015, USA. He is the recipient of Gallieno Denardo award of International Commission of Optics and ICTP for his contribution to Optics and Photonics, 2017. He has also received best thesis award, Indian Laser Association, 2009. He is a life member of Indian Laser Association and a regular member of Optical Society of America and SPIE, USA. In addition to his regular research activities, Dr. Samanta promotes Optics and Photonics among school and college students in India through hands on experiments.
Wrinkles and cracks are ubiquitous in thin films cycled through externally applied strain. Wrinkles were traditionally regarded as undesirable features, while cracks have represented material failure. Further advancements brought wrinkles within the scope of mathematical scaling description, while the physics of cracks is still at a nascent stage. Electrically conducting materials lend an entirely new paradigm to this subject. The elastic response of graphene and conducting polymer systems has a strong bearing on their electrical properties. In this talk, experiments related to cracks and wrinkles in layered graphene films and in conducting polymer thin films on flexible substrates will be presented. Quasi-periodic crack propagation in layered graphene films under strain has a non-trivial dependence on film thickness. While flexible optoelectronic applications require the film to be strain-resistant, strain sensing applications require them to be otherwise. We demonstrate how geometrical parameters relate to the cracking behaviour, thus allowing tailor-designed material suited for diverse applications. In context of conducting polymer films, distinct ‘wrinkle-dominated’ and ‘crack-dominated’ transport regimes are observed. The strain cycled films show a peculiar hysteresis behaviour for the electrical resistance, whose physical origin will be discussed.
Dr. Manu Jaiswal is an Associate Professor in the Department of Physics, IIT Madras. He did his Bachelor’s degree in Physics (Hons.) from St. Stephen’s College, Delhi followed by an Integrated-PhD from Indian Institute of Science, Bangalore. He then pursued post-doctoral work at Max Planck Institute for Polymer Research in Mainz and at National University of Singapore. He joined IIT Madras in 2011. His research interests include the physics of low-dimensional systems. Some recent research problems investigated by him include the snap-through instability of graphene membranes, structure and transport of confined water in graphene oxide, dynamical properties of graphene, and the interplay of wrinkles and cracks with electrical transport.
Spin wave based spintronics is known as “magnonics”. Magnon is the quasi-particle for spin waves as phonons for acoustic waves. Magnonic devices utilize spin waves to transmit/process information. Spin waves are found to be promising for miniaturization of microwave electronics operating at GHz frequencies [1]. The building blocks of a magnonic device include generation, manipulation and detection of spin waves. One of the major challenges of such devices is the requirement of a bias magnetic field during GHz signal processing/transmission due to the anisotropic dispersion characteristics of spin waves. It makes magnonic technologies unfit for device integration at the nanoscale. Here, we shall discuss current developments on bias-field-free solutions mainly for the two following areas: first, magnetic waveguides/conduits through which spin waves propagate [2,3] and second, nanostructures that are suitable for tunable microwave properties [4]. Results from micromagnetic simulations, ferromagnetic resonance (FMR) and micro focused Brillouin light scattering (micro-BLS) experiments will be presented.
References:
Dr. Haldar is an Assistant Professor at IIT Hyderabad. He has obtained his PhD degree from IIT Bombay (Mumbai, India) in 2011 in the area of magnetic alloys. He subsequently worked as a Post-doc at Colorado State University (Fort Collins, USA), as a Scientist-C at S. N. Bose National Centre (Kolkata, India) and as a Post-doc at National University of Singapore (Singapore) before joining IIT Hyderabad (India). His research interests include spin wave based spintronics, Brillouin light scattering spectroscopy and nanofabrication. He has co-authored 28 papers, 2 US patents and 2 book chapters. He was awarded Ramanujan Fellowship in the year of 2016.
This talk will review the integration of oxides and fully printable organics for newly emerging application areas related to wearables and the Internet of Things. We will discuss the critical design considerations to show how device-circuit interactions should be handled and how compensation methods can be implemented for stable and reliable operation. In particular, the quest for low power becomes highly compelling in wearable devices. We will discuss transistor operation in the different regimes, and review device properties when operated in the deep sub-threshold regime or in near-OFF state, addressing the pivotal requirement of low supply voltage and ultralow power leading to potentially battery-less operation.
Professor Arokia Nathan leads a multi-disciplinary research group whose primary focus is on the heterogeneous integration of materials and processes, sensors, energy harvesting and storage devices pertinent to wearable technologies. Formerly a Chair Professor of Photonic Systems and Displays at the University of Cambridge, he is currently the Chief Technical Officer of Cambridge Touch Technologies, a company spun out of the University developing advanced interactive technologies.
Photovoltaic (PV) cell technologies, including, materials, cells and modules continue to show amazing development. While Halide Perovksite-based cells mostly steal the limelight, I will assess them within the broader picture of other (near)commercial cell types. This as-sessment is not restricted to solar to electrical power conversion efficiencies, but considers also factors that affect power output for each cell type. Also improvements in stabilities and decreases in costs, which often are the result of technological advancements, are considered, as well as better control over interfaces and materials. Comparing parameters of different PV cell types may help to see how far each type can progress in the coming years, because, even though accurate developments cannot be predicted, often cross-fertilization occurs, making achievements in one technology an indicator of what’s to come in the next one.
* collaborations with Gary Hodes, WIS, and Pabitra Nayak, Henry Snaith, Oxford U)
Scanning probe lithography (SPL) methods like dip-pen nanolithography (DPN), polymer pen lithography (PPL), microchannel cantilever spotting (µCS) and related techniques offer unique opportunities for the future of printable electronics. These methods work maskless, have a broad compatibility with many materials due to their mild process parameters, and offer the option of multiplexing (i.e. deposition of different substances next to each other or in intertwined patterns in the same process step). Additionally, they offer high resolution, ranging from the micron to the nanometer scale and allowing significant miniaturization in comparison to inkjet printing approaches. SPL techniques can also be used in conjunction with conventional lithography processes, e.g. for deposition of sensitive substances on existing prestructures for sensor functionalization or delivery of active materials to a device. Here we will present some examples for applications of SPL methods in the realm of devices functionalization and a particular interesting novel approach of writing conductive structures via SPL with liquid metal.
Michael Hirtz is leader of the group for Dip-Pen Nanolithography and related Techniques situated in the research unit of Prof. Fuchs at the Institute of Nanotechnology (INT) of the Karlsruhe Institute of Technology (KIT), Germany. He holds a PhD in physics and in medical sciences from the University of Münster. After doing research on self-organization phenomena in phospholipid films generated by Langmuir-Blodgett technique during his PhD, he is now focusing on advancing Dip-Pen Nanolithography and other Scanning Probe Lithography methods for applications at the interface of physics, surface chemistry and biology.
For an overview of his work and publications, please visit:
https://www.researchgate.net/profile/Michael_Hirtz
http://www.researcherid.com/rid/C-8821-2011
Lars-Erik Wernersson received the M.S degree the Ph.D. degree in Solid State Physics at Lund University in 1993 and 1998, respectively. Since 2005 he is Professor in Nanoelectronics at Lund University, following a position at University of Notre Dame 2002/2003. His main research topics include nanowire- and tunneling- based nanoelectronic devices and circuits for low-power electronics and wireless communication. He has authored/co-authored more than 200 scientific papers. He has been awarded two individual career grants and he served as Editor for IEEE Transaction on Nanotechnology. He is coordinator for the H2020 project INSIGHT.
A color sensor typically consists of an array of detectors in combination with multiple color filters. To achieve the capability of a single pixel color sensor, we have engineered photodetector with graded bandgap perovskite as the active layer. The active layer comprises of a mixture of 2D perovskite quantum wells structures and 3D perovskites. The various bandgaps in 2D quantum is attributed to the order of PbI6 octahedral stacking. In a self-assembled perovskite film, the high bandgap quantum wells assembles to the bottom and low bandgap towards the top of the film, creating an overall gradation in the bandgap. The photocurrent rise and decay profiles of these structure have unique wavelength dependent characteristics. The unique color signatures in the decay component of the light pulse are based on cumulative effects of charge generation profile in the graded bandgap active layer and transport across capacitive pathways. Devices where the short circuit photocurrent showed a complete polarity reversal for certain wavelength. We propose a generic wavelength dependent expression to arrive at a model to account for colour sorting over a wide spectrum.
*in collaboration with N. Ganesh, Ravichandran Shivanna, Richard Friend
K.S.Narayan (MSc IIT Bombay, PhD The Ohio State Univ, Professor and Dean (R&D), Silver Jubilee Professor, Jawaharlal Nehru Centre for Advanced Scientific Research), research activities is in the area of optoelectronics and photophysics of macromolecular/organic/nano/hybrid materials, and device development. Major highlights over last two decades include the discovery of polymer based optical-field effect transistors, 1-D and 2-D position sensors, vacuum free processing of solar cells, and range of strategies to enhance perfromance of solar cells and light emitting diodes. These methods and approach are currently being utilized for developing hybrid perovskite based devices in his laboratory. He has developed microscopic and spectroscopic techniques specifically to understand the various optical and electrical phenomena in these low-dimensional materials. He has also contributed to research area of these soft-electronic polymers in biomedical arena where these materials have exhibited utility in tissue engineering and for vision prosthetic elements. Of lately, he has developed non-contact sensing methods to pick electrical activities at cellular level length scales, which can be scaled to tissue and whole-organ level. His other current pursuits include developing noise measurement and scanning techniques to predict the full life cycle of photovoltaic modules. Besides this effort in pursuing fundamental aspects of organic optoelectronic device, he is keen to translate these devices and techniques to the commercial space.
In most applications involving resonant mechanical devices, NEMS included, the assumption is that higher quality factor is always better. We have recently shown (Science 360 eaar5220) a fundamental improvement in stability and in resonant performance in air-viscously-damped, purposefully low-Q devices. The devices were nano-optomechancial systems (NOMS), though the device architecture is not important to the fundamental stability effect. At the heart of the improvement was the following finding: that the traditionally assumed stability limitation imposed by equivalent noise amplitude can be further improved simply by limiting bandwidth in the proper feedback configuration. This presentation will discuss this finding and its potential repercussions for resonant sensors and crystal oscillators.
Wayne Hiebert is a group leader and senior researcher at the national research council of Canada’s nanotechnology research centre. He holds an adjunct with the university of Alberta department of physics and has been active in the field of NEMS since 2003
As the GaN solid state lighting technology is maturing, the interests of research community are shifting towards ultrawide bandgap semiconductors such as BN, AlN, Ga2O3, and their alloys to looking for new important technologies including UV optoelectronics and power electronics. This presentation will focus on the research progress made by the Advanced Semiconductor Laboratory at KAUST with collaborators, spanning from materials, semiconductor physics, equipment to devices of different geometries.
Professor Xiaohang Li is the Principal Investigator of Advanced Semiconductor Laboratory at KAUST. He received Ph.D. in Electrical Engineering from Georgia Tech in 2015. He is a pioneer of deep UV laser research and has made significant and innovative contributions in the B-III-N alloys, III-oxides, and visible emitters. He has authored >170 journal and conference publications, delivered >60 invited and plenary talks, and authored three book chapters. He is a reviewer of over 30 journals including Nature Photonics. He is the recipient of many prestigious awards including AACG Harold M. Manasevit Young Investigator Award and SPIE D. J. Lovell Scholarship.
Boris Hudec and Tuo-Hung Hou
Department of Electronics Engineering and Institute of Electronics, National Chiao-Tung University, ED-409,
1001 University Road, Hsinchu 300, Taiwan, R.O.C. Corresponding author e-mail: thhou@mail.nctu.edu.tw
Current implementations of hardware neural networks (HNNs) realized using CMOS ICs are rather resource hungry, as each synaptic weight is encoded as digital quantity, typically using an SRAM array. Huge recent interest in AI has therefore catalyzed the devotion of scientists, big tech companies as well as booming number of AI chip startups to reinvent analog computing. In one such approach (resistive computing) the synaptic connections between layers of neurons in HNN are represented by a crossbar array of analog resistive synapses (analog memristors). Each such array thus represents a weight matrix where current flowing between input and output neurons depends on the weight (resistance) of each synapse, which in turn depends on the previous electrical stimuli (weight update, i.e., learning).
The focus of this talk will be on the physics, and related design aspects, of a fully analog, oxide-based nano-electronic resistive synapses developed using atomic layer deposition (ALD), a mass production technology providing homogeneous 3D deposition with nm-scale film thickness control and necessary stoichiometry tuning, as the ultimate pathway to ultra-scaled HNNs. A prototypical multi-layer perceptron HNN adopting such synaptic array will be briefly introduced and necessities of a device-algorithm co-design, required for this bottom-up approach, will be mentioned.
Boris Hudec obtained his PhD. degree in microelectronics at the Institute of Electrical Engineering of Slovak Academy of Sciences, in Bratislava, Slovakia, in 2012. From 2014 he joined the Department of Electronics Engineering at the National Chiao Tung University (NCTU), in Hsinchu, Taiwan, as a research associate. His current research interests are on nanoscale device technologies with a particular focus on atomic layer deposition of high-k dielectrics and engineering of resistive switching structures for applications in emerging non-volatile memory devices and neuromorphic computing. On the characterization side he is studying device physics using advanced X-ray spectroscopy techniques.
Electronic Design Automation (EDA) has has made large scale integration in electronics possible. The Technology Computer Assisted Design (TCAD) branch of EDA models fabrication processes and device performance, and as such helps guide the technology development process. EDA/TCAD tools have become the bread and butter in the development of technologies and circuits, and, with increasing development costs, are more and more relied upon to give accurate predictions on power, performance, area, cost, and reliability. EDA/TCAD tools are thus essential to keep development cost and, consequently, unit costs low. The demands for industrial TCAD software are high: tools need to be predictive, versatile w.r.t. application, numerically robust, and fast. Design-technology co-optimization (DTCO) has emerged as the new TCAD application paradigm which aims to connect equipment, process, device, and circuit simulation in a common work-flow.
Global TCAD Solutions GmbH (GTS) was founded 2008 by graduate students at the Vienna University of Technology in Austria as a TCAD software start-up. But how can a start-up make meaningful contributions to the state of the art of TCAD in the corporate-dominated EDA-world? The answer is innovation; it is the key to survival for any start-up, and it is what the TCAD community needs right now. This talk highlights the key advances GTS has made with particular focus on physics-based transport and device modeling, and DTCO.
Dr. Zlatan Stanojevic received his Master and PhD degrees in electrical engineering from the Vienna University of Technology in 2009 and 2016, respectively. His current position is Chief Technology Officer (CTO) of Global TCAD Solutions located in Vienna, Austria. The particular focus of Dr. Stanojevic’s work has been on low-dimensional systems, i.e. FinFETs, nanowires, nanosheets and SOI. During his research career, Zlatan Stanojevic was responsible for the development of state-of-the-art computational tools for simulating low-field and high-field transport in low-dimensional systems, based full band structure and the Boltzmann transport equation. He is the main author of the Vienna Schrödinger-Poisson quantum simulator and the GTS Nano Device Simulator (NDS).
Farid Medjdoub is a CNRS senior scientist and leads the wide bandgap activities at IEMN in France since 2014. He received his Ph.D. in Electrical engineering from the University of Lille in 2004. Then, he moved to the University of Ulm in Germany as a research associate before joining IMEC as a senior scientist in 2008. Multiple state-of-the-art results have been realized in the frame of his work. Among others, world record thermal stability up to 1000°C for a field effect transistor, best combination of cut-off frequency / breakdown voltage or highest lateral GaN-on-silicon breakdown voltage using a local substrate removal have been achieved.
His research interests are the design, the fabrication, and characterization of innovative GaN-based devices. He is author and co-author of more than 130 papers in this field. He holds several patents deriving from his research. He serves as an Editor for Superlattices and Microstructures journal. He is also a reviewer for various journals and is a TPC member in several conferences.
This talk will discuss some potential solutions for next generation lateral GaN-on-Silicon power devices targeting high voltage applications operating at 1200 V and above, which pave the way to much lower on-resistance as compared to other existing technologies operating above 1 kV.
Nitrogen Vacancy (NV) color centres in diamond are a leading platform for nanoscale sensing and biomedical imaging. NV centers can be spin polarized and readout optically at room temperature and have fluorescence that does not blink or bleach. To date, however, NV-diamond magnetic imaging has been performed using “real space” techniques, which are either limited by optical diffraction to ≈250 nm resolution or require slow, point-by-point scanning for nanoscale resolution. I will discuss an alternative technique of Fourier magnetic imaging using NV-diamond that we have recently demonstrated. We employ pulsed magnetic field gradients to phase-encode spatial information on NV electronic spins in wavenumber or “k-space” followed by a fast Fourier transform to yield real-space images with nanoscale resolution down to ~ 5nm. I will also discuss a recent experiment where we experimentally demonstrated selective coherent manipulation of an array of four NV spin sites, equally spaced by ~100 nm, using frequency encoding techniques inspired by magnetic resonance imaging (MRI).
Chinmay Belthangady graduated with a BTech in Engineering Physics from IIT-Bombay (2004) and a PhD in Applied Physics from Stanford University (2010). After a postdoctoral stint at Harvard University and the Harvard-Smithsonian Center for Astrophysics he worked as a Research Scientist at Google-[x], Google’s semi-secret R&D arm. Currently he is a Senior Scientist at the Chan-Zuckerberg Biohub. Chinmay’s research interests include atomic physics, quantum optics, quantum communication, quantum-assisted metrology, microscopy, bio-imaging and deep learning.
Combinatorial control on electronic properties of Graphene analogous systems can be accomplished by fabricating their van der Waal stacks. Such heterostructures (HS), with modulated interlayer coupling act like a tuning knob to control doping and hybridization attributes of the underlying layer and thus helps to modulate the excitons and transport of the system. We focus on three different categories of HS, viz., 1) Semiconductor-semiconductor, 2) Weyl semimetal – normal metal and 3) conventional metal-metal HS. In (1), systems like MoSe2/GO, MoS2/TiO2 and MoS2/ReS2 will be discussed, where we obtain a finely tuned doping behaviour from n to p type depending on the type and concentration of functional ligands, by selecting different terminating surface at the interface and also by varying the number of layers of the constituting HS. For category (2), in TaAs/Au and TaAs/Ag interfaces, we found that the metallic layers have flipped the original spin-polarization of the pristine system, introduce different doping pattern and also modified the underlying symmetry and Fermi surface of the pristine system. For category (3), in Au/Ag normal and nanostructured interface, we have investigated the band crossing behaviour near Fermi-level and also the Fermi-surface restructuring compared to the individual metallic layers.
Completed graduation and post graduation from University of Calcutta, Ph D from University of Mumbai, Post doctoral from MPI-Stuttgart. Current Affiliation is scientist at Bhabha Atomic Research Centre, Google scholar
link: https://scholar.google.com/citations?hl=en&user=9olqkkcAAAAJ
Terahertz (THz) quantum cascade lasers (QCLs) are semiconductor-based compact coherent sources which employ inter-subband transitions and carrier recycling in periodically stacked quantum-wells. Such THz sources show narrow emission linewidths and can deliver quite high output power at low temperature. The operating-frequency of GaAs based THz QCLs covers from 1.2 to 5.4 THz. However, the operation temperature has been limited up to 200 K since 2010. In the past decade, significant efforts have been dedicated to overcome this difficulty. Nevertheless, the progress has been very limited.
Recently we have revealed carrier leakage channels from the upper laser level via high/excited energy states. The leakage channel is due to unintentional closing or alignment, which is distinct from the thermally activated leakage channels. By tuning the energy of such high-energy states via modifying well/barrier potential profiles, the leakage current can be suppressed. We then propose a new type asymmetric two-well indirect injection THz QCLs, which use different well potential depth between the neighbour wells. The simulated results suggest the new design would work at 250 K.
The potential GaN/AlGaN THz QCL has been analysed theoretically. GaN has much larger phonon energies (91 meV vs 36 meV for GaAs), and can in principle allow THz QCLs to operate at room temperature or even higher. They would be key coherent sources in the unexplored terahertz frequency range of 5.4~12 THz, at which GaAs THz-QCLs are not able to work due to the Reststrahlen band. The strong electron-LO-phonon interaction in GaN, with a Fröhlich constant 16 times stronger than in GaAs, could be a limitation in terms of lifetimes and level broadening. A careful study of the broadening mechanism and GaN’s potential for THz QCLs will be discussed. Preliminary experiments to grow and fabricate GaN THz QCLs will be addressed as well.
Prof Ke Wang received the B. Sc degree from Nanjing University, China, in 2000, M.Phil degree from University of Hong Kong in 2003, and PhD degree from University of Strathclyde, Glasgow, United Kingdom, in 2007, respectively, all in physics. He joined Nanishi-Araki Lab at Ritsumeikan University, Japan, in 2008, and there he received JSPS Fellowship, and started works on III nitride MBE technologies. In 2013 he joined Chiba University, Japan, as a special associate professor, working together with Prof Akihiko Yoshikawa. Since 2016 he has been a research scientist in RIKEN, Japan, and working on DUV-LEDs and GaN based quantum cascade lasers. He is now a professor in Nanjing University. He has been engaged in the fields of semiconductor devices and physics, and has extensive experience in MBE technologies.
B. Penkovsky, M. Bocquet, T. Hirztlin, J.-O. Klein, E. Nowak, E. Vianello, J.-M. Portal and D. Querlioz
The advent of deep learning has substantially accelerated machine learning development during the last decade. Multiple tasks such as computer vision have been drastically improved and even outperformed the human accuracy. However, those deep learning implementations require almost two orders of magnitude more power comparing to the human brain. Moreover, with the end of the Moore’s law, new hardware insights are necessary to keep steady the progress. With new memories available, such as Resistive and Magnetoelectric Random Access Memory (RRAM and MRAM), thanks to the latest advancements in nanotechnology, emerging Binarized Neural Networks (BNNs) are promising to reduce the energy impact of the forthcoming machine learning hardware generation. The simplicity and energy efficiency of BNNs makes them especially suitable for wearable devices, including but not limited to biomedical, healthcare, and sport application domains. In this talk, we discuss our latest BNN developments along with our vision towards the future of energy-efficient smart devices.
Dr. Bogdan Penkovskyi is a postdoctoral CNRS researcher at Paris-Sud University, France. His research interest in neuromorphic or brain-inspired computing originated during his MSc in Applied Mathematics (2007-2013) at the National University of Kyiv-Mohyla Academy, Ukraine. In 2017, he has obtained a PhD degree in Optics and Photonics at the University of Bourgogne Franche-Comte, France applied to nonlinear transient computing based on delayed-feedback systems. His PhD project has resulted in a standalone real-time FPGA-based neuromorphic processor capable of classification and prediction tasks. The related Brain-Inspired Photonic Processor project has been successfully evaluated by the National Research Agency (ANR) in 2017. Bogdan has been also worked on the first demonstration of so-called chimera states in nonlinear delay dynamics. Currently, he works at C2N department pursuing the goal of energy-efficient computing hardware for biomedical applications.
A unified model for drain current local variability in MOS transistor due to random discrete dopants is discussed, which incorporates both inversion charge fluctuation and correlated mobility fluctuation. Due to fluctuations in the number of impurity atoms, the number of inversion charge carriers fluctuates. This leads to local fluctuation in inversion charge density. Due to channel doping variation, the inversion channel charge and effective field fluctuates. The correlated mobility fluctuation includes fluctuation of inversion carrier mobility limited by Coulomb impurity scattering and fluctuation of carrier mobility due to electric field fluctuation. In the weak inversion mode, inversion charge fluctuation and mobility fluctuation due to Coulomb impurity scattering limited component are the causes of the drain current variability. In the strong inversion mode, apart from the former two, electric field fluctuation plays significant role. The compact variability model captures physical insight of the impact of channel profile parameters on the drain current local variability. This is useful for reducing the effects of variability. Good match between the model-predicted results and calibrated TCAD atomistic simulation results for all possible bias regions, several geometries and temperatures validate the model. The model being compact in nature is suitable for implementation in SPICE simulation framework.
Soumya Pandit is an Assistant Professor in the Institute of Radio Physics and Electronics, University of Calcutta, India. Dr. Pandit acted as lead project scientist in several R&D projects sponsored by semiconductor industries like National Semiconductor, USA and government agencies like MeitY. He had taped out several integrated circuits in 0.18μm CMOS technology and published more than 35 numbers of papers in leading international journals and conferences. He has authored a book and co-authored several book chapters’ published internationally reputed publishers. He is currently Chief Investigator of Special Manpower Development Program-Chip to System Design (SMDP-C2SD) Project at the University of Calcutta.
GaN HEMTs offer a combination of unmatched breakdown voltage and low on-resistance, delivering spectacular power switching circuits with higher efficiency, higher operating frequency and lower losses than the incumbent silicon technologies. However take-up has been slow partly as a result of difficulties in controlling device instabilities. An especial problem has been dynamic on-resistance, a transitory increase in the device on-resistance following operation at high drain bias.
All GaN HEMTs rely on a semi-insulating epitaxial buffer structure to suppress parallel ungated source-drain leakage paths. This talk will explain why small, apparently insignificant, leakage paths in the buffer have a profound impact on transistor operation. Surprisingly, without the presence of leakage these transistors are essentially unusable, resulting in almost infinite dynamic on-resistance. Guidelines for the design of the buffer and recently discovered techniques for the suppression of dynamic on-resistance based on the deliberate control of leakage will be discussed.
Mike Uren has 40 years experience of FETs, including Si CMOS, SiC MESFETs, and GaN RF and power HEMTs. He did pioneering work on 2DEG transport, telegraph noise, porous silicon, and interface traps, and was technical lead for the QinetiQ Ltd RF MMIC process. Since 2011 he has been Research Professor at the University of Bristol and has been especially interested in the impact of the epitaxial buffer on RF and power device performance. He developed new techniques to interpret the buffer transport, as well as the “leaky dielectric” model which provides a straightforward explanation for buffer current collapse in RF and power devices.
Using printing is expected to enable low-cost mass-fabrication of large-area electronics. Different fabrication paradigms such as sheet-to-sheet (S2S) and roll-to-roll (R2R) are under development. These set different requirements and limitations for the processability of the materials, for example, in terms of annealing conditions and positioning accuracy of consecutive device layers. The influence of the fabrication process characteristics on different applications will be discussed. In particular, the talk will focus on metal-oxide materials and their use in the printing process for electronics devices. Especially, thin-film transistors (TFT) will be considered for S2S and R2R fabrication. In addition, the talk will cover recent developments in high-resolution printing processes that have been used for conductor structures and TFTs for low-frequency applications but also for high-frequency communication devices such as antennas.
D.Sc. (Tech.) Ari Alastalo did his M.Sc. (Tech.) degree at the Aalto University (Helsinki University of Technology at that time) in 1997 on the quantum theory of magnetic impurities in BCS superconductors. Then he moved to Nokia Research Centre, where he worked on array antenna research for WLAN networks. In 2002, he came to VTT to work on microelectromechanical systems (MEMS and RF) resulting in his D.Sc. (Tech.) degree from Aalto University in 2006. After that, he started as a team leader in printed electronics at VTT. In 2013, the applicant received a title of Docent in applied materials physics from the Aalto University. Currently he works as a Principal Scientist at VTT and holds IPMA-C certificate in project management. He has authored 72 journal and conference articles and holds 12 patents.
The nature of heat flow plays a key role in microfabricated devices, in some cases determining the functionality of the device, and in some cases, limiting its performance. This talk will present the fundamentals of heat transfer in microfabricated devices as well as two specific engineering applications. Key aspects of microscale heat transfer will be summarized, and heat transfer design of MEMS devices will be discussed. Heat transfer aspects of two distinct MEMS devices – for studying thermotaxis in nerve cells and for measuring thermal properties of thin materials – will be presented.
Ankur Jain is an Associate Professor in the Mechanical and Aerospace Engineering Department at the University of Texas, Arlington, USA. He directs the Microscale Thermophysics Laboratory (www.uta.edu/mtl), which carries out experimental and theoretical research on heat transfer and energy conversion in Li-ion batteries, microscale thermal transport, bioheat transfer, microelectromechanical systems, etc. He received the Lockheed Martin Excellence in Teaching Award (2018), UTA College of Engineering Outstanding Early Career Award (2017), NSF CAREER Award (2016) and the ASME EPP Division Young Engineer of the Year Award (2013). Dr. Jain was among a small group of US-based researchers invited by the US National Academy of Sciences to participate in the 5th Arab-American Frontiers of Science, Engineering, and Medicine Symposium in 2017. He received his Ph.D. (2007) and M.S. (2003) in Mechanical Engineering from Stanford University, where he received the Stanford Graduate Fellowship (SGF) and his B.Tech. (2001) in Mechanical Engineering from the Indian Institute of Technology (IIT), Delhi with the highest GPA among the class of Mechanical Engineering. He has published 56 high quality journal articles on topics related to energy conversion and heat transfer in macroscale and microscale engineering materials and systems.
The interest in two dimensional (2D) materials is rapidly spreading across all scientific and engineering disciplines due to their exquisite physical properties which not only provides a platform to investigate new and intriguing phenomena but also promises solutions to many imminent technological challenges. In this talk I will provide a new perspective on 2D materials that includes their widespread applications in conventional electronics, flexible electronics, straintronics, self-powered electronics, optoelectronics and even in brain inspired electronics and hardware security. I will also talk about benchmarking of various synthesis techniques for large area manufacturing of various 2D materials.
I completed BE degree (2007) in Electronics and Telecommunication Engineering (ETCE) from Jadavpur University, India and PhD degree (2013) in Electrical and Computer Engineering (ECE) from Purdue University, USA. I worked at the Department of Defense’s Argonne National Laboratory as a postdoctoral research scholar during 2013-15 and as an Assistant Research Scientist during 2015-16. I joined the Department of Engineering Science and Mechanics (ESM) and Material Research Institute (MRI) at the Pennsylvania State University as an Assistant Professor from January, 2016. My research group primarily focuses on the experimental investigation of novel nano materials especially 2D materials like MoS2, Black Phosphorus, Graphene and 1D materials like CNTs and Nanowires for innovative device ideas. My research group (https://sites.psu.edu/sdas/) works on high performance and low power electronics, flexible electronics, optoelectronics, bioelectronics and energy harvesting devices.
Dr. Agrawal joined UTS in January 2018 with time evenly split between roles of Associate Professor in the School of Electrical and Data Engineering within the Faculty of Engineering and IT, and Director of the Women in Engineering and IT programme.
Previously Dr. Agrawal worked at City, University of London from 2005-2017 in the Department of Electrical Engineering. She was Royal Society postdoctoral fellow, and her PhD was on modelling methods for optical components, completed at the Indian Institute of Technology Delhi in 2005.
Dr. Agrawal’s research interests lie in optics: modelling of photonic components such as solar cells, optical fibers, sensors, lasers etc. She is an expert on numerical methods for optics such as Finite Element Method (FEM). She has written a book on FEM, and edited a book on trends in computational photonics. She is also an Associate Editor for the IEEE Photonics Journal.
Tanushree H. Choudhury received her Ph.D. in Materials Science from Materials Research Centre, Indian Institute of Science, Bangalore in 2013. Her thesis work focused on the development of thermally stable anodized zirconia nanostructures. In 2014 she joined the Department of Materials Science and Engineering, Pennsylvania State University as a postdoctoral researcher in Prof. Joan Redwing’s lab to work on chemical vapor deposition of transition metal dichalcogenides (TMDs). In 2016, she was promoted to Assistant Research Professor in the 2D Crystal Consortium- Materials Innovation Platform at Penn State where she works on wafer scale growth of epitaxial TMDs using metal organic chemical vapor deposition. Her research focuses on understanding fundamental mechanisms of crystal growth and epitaxy of TMDs and the effect of defects on nucleation of TMDs.
Monolayer transition metal dichalcogenides (TMDs, MoS2, WSe2, etc.) possess a range of intriguing optical and electronic properties including direct bandgap, high exciton binding energies, valley polarization, etc. Current research is typically carried out using flakes exfoliated from bulk crystals or monolayer TMD triangular crystals grown by powder source chemical vapor deposition (CVD) which are challenging to scale to large area. Our research is aimed at the development of an epitaxial growth technology for layered dichalcogenides, like that which exists for III-V and other compound semiconductors, based on gas source chemical vapor deposition (CVD). This approach provides a high overpressure of chalcogen species needed to maintain stable growth at elevated temperature and excellent control of the precursor partial pressures to achieve monolayer growth over large area wafers.
Our initial studies have focused on the epitaxial growth of binary TMD monolayers including MoS2, WS2, WSe2 and MoSe2 using metal hexacarbonyl and hydride chalcogen precursors to deposit on 2” sapphire substrates in a cold-wall CVD reactor. Growth of sulfur-containing TMDs require a significantly higher chalcogen/metal inlet gas ratio compared to selenium-containing TMDs due to the reduced sticking coefficient of sulfur on the sapphire surface at typical growth temperatures (600-950oC). A multi-step precursor modulation growth method was developed to independently control nucleation density and the lateral growth rate of monolayer domains on the substrate. This approach also enables measurement of metal-species surface diffusivity and domain growth rate as a function of growth conditions providing insight into the fundamental mechanisms of monolayer growth. Using this approach, uniform, coalesced monolayer and few-layer TMD films were obtained on 2” sapphire substrates at growth rates on the order of ~1 monolayer/hour. In-plane X-ray diffraction demonstrates that the films are epitaxially oriented with respect to the sapphire with narrow X-ray full-width-at-half-maximum indicating minimal rotational misorientation of domains within the basal plane. Post-growth transmission electron microscopy carried out on monolayers removed from the sapphire by a wet transfer method demonstrate that the films are single crystal and include anti-phase grain boundaries that result from a merging of 0o and 60o oriented domains that form on sapphire. Growth of (Mo,W)S2 alloy monolayers was also achieved over the entire composition range by controlling the inlet gas phase ratio of Mo and W hexacarbonyl precursors. Applications and challenges of this technique for the growth of vertical 2D heterostructures will also be discussed.
The authors acknowledge financial support of the U.S. National Science Foundation through the Penn State 2D Crystal Consortium – Materials Innovation Platform (2DCC-MIP) under NSF cooperative agreement DMR-1539916 and EFRI 2-DARE Grant EFRI-1433378.
Harsha Penugonda, Amita, Sushant Mittal, Abhimanyu Shekhawat, Udayan Ganguly
Scaling and new device architectures improve nanoscale device performance. However, it drives manufacturing control towards a more stringent specification. Two examples are as follows. First, from the perspective of structural control, the fin width reduction becomes comparable to Line Edge Roughness (LER). Thus, fin-to-fin variations are substantial in high volume manufacturing. Second, from the perspective of materials control, the gate metal grains have orientation dependent work-functions. When the grain size becomes comparable to gate length, then gate-to-gate variations leading to effective Work-function variations can not be neglected. These variations translate to transistor performance variation – primarily, the threshold voltage ( ), as well as other variations like on current ( ), sub-threshold slope ( ). These variations are non-Gaussian and require device level simulation for each device to generate statistics – which is computationally intensive when simulated in TCAD. The ultimate impact to circuit performance requires compact models. In this talk, we will present our six-year adventure of understanding the physics of variability through TCAD (using individual devices-level self-consistent solutions), developing of analytical models to mimic the distributions of devices and finally finding compact forms. Our group has derived the first such physics based compact models for multi-gate transistors. Such compact models can be integrated in circuit simulations to understand block level to system level performance.
Udayan Ganguly received the B.Tech. degree in Metallurgical Engineering from the IIT Madras, in 2000 and the M.S. and Ph.D. degrees in Materials Science and Engineering at Cornell University, Ithaca, NY, in 2005 and 2006 respectively. In 2006, Udayan joined Applied Materials to serve as the technical lead for Flash Memory Applications Development at Applied Materials’ Front End Product Division, Sunnyvale, CA. He has joined Dept. of Electrical Engineering in 2010. He has authored/ co-authored 45+ journal, 75+ conference and 25+ patents (applied/granted). His research interests are in semiconductor device physics and processing technologies for advanced memory, computing, and neuromorphic systems. He has contributed to the TIFAC National Vision for ICT 2035. He works to augment national semiconductor manufacturing capability at Semi-Conductor Labs, Chandigarh, for which he has won the Dr. PK Patwardhan Technology Development Award 2018.
It is well accepted that Spin Transfer Torque Memory has the potential to be an universal memory since it scores well on metrics like non-volatility, endurance, low operating voltages and ultra fast switching. Rowhammer is a known security vulnerability in recent Dynamic Random Access Memory (DRAM) devices, where repeated access to an array of memory can flip the bits in the adjacent row. Many published scenarios highlight that scaled DRAM below 32nm is exposed to potential hacking attacks because of the Rowhammer problem, owing to reduced spacings in DRAM bits. In this talk we will demonstrate that STT-RAM based memory not only has the potential to scale to future nodes, it does not show security vulnerabilities like Row-hammer that other candidates like DRAM manifest. A unique quantitative machinery for device engineers to model p-MTJ circuits will be presented based on a physics based switching model. The switching model combines elements of quantum transport using the non-equilibrium Green’s function (NEGF) formalism and the spin diffusion equation which provides a qualitative as well as a quantitative agreement with switching voltages in spin torque experiments. The model is further used to explain opposing patterns of switching voltage asymmetry observed in different experiments.
Dr. Samarth Agarwal is a Senior Member of Technical Staff at GLOBALFOUNDRIES, Bangalore where he works on MRAM technology. He has held positions at the IBM Semiconductor R&D Center and COMSOL Multiphysics. He has been involved in the development of scientific software and over 8000 users have accessed simulation tools authored by him on the science and engineering gateway nanoHUB.org. Dr. Agarwal has a Ph.D. in Physics from Purdue University and a B.Tech in Engineering Physics from IIT, Bombay. He has several papers and patents in the area of device variability, quantum transport and micro-magnetics.
There is a significant need to build efficient non-von Neumann computing systems for highly data-centric artificial intelligence related applications. Brain-inspired computing is one such approach that shows significant promise. Memory is expected to play a key role in this form of computing and in particular, phase-change memory (PCM), arguably the most advanced emerging non-volatile memory technology. Brain-inspired computing is likely to be realized in multiple levels of inspiration given a lack of comprehensive understanding of the working principles of the brain. In the first level of inspiration, the idea would be to build computing units where memory and processing co-exist in some form. Computational memory is an example where the physical attributes and state dynamics of memory devices are exploited to perform certain computational tasks in place with very high areal and energy efficiency. In a second level of brain-inspired computing using PCM devices, one could design a co-processor comprising multiple cross-bar arrays of PCM devices to accelerate training of deep neural networks. PCM technology could also play a key role in the space of specialized computing substrates for spiking neural networks and this can be viewed as the third level of brain-inspired computing using these devices
Dr. Ajit Paranjpe, Chief Technology Officer – Veeco Instruments
The promise of ubiquitous connectivity combining high bandwidth (up to 10 GB/s) with ultra-short latency (down to 1 ms) extends applications for fixed and mobile networks beyond cellular communication to broadband connectivity, augmented / virtual reality (AR/VR), autonomous vehicles, and internet of things (IoT). Early deployment and field trials of 5G networks by multiple service providers has begun endorsing the widespread interest and potential of 5G-driven applications and communications.
In this talk, we will review the architectural and device implications of adding the new bands (sub 6 GHz and mmWave) to RF front-ends, and the resulting impact on RF device capability and performance. Compound semiconductor based power amplifiers (GaAs, GaN and InP) are leading candidates for 5G RF front-ends due to their added efficiency at high output power and compact foot-print for multiple input / output (MIMO) architectures.
GaAs based hetero-junction bipolar transistors (HBTs) are likely to be replaced by pseudomorphic high-electron-mobility transistors (p-HEMT), while GaN on Si HEMTs will partially supplant GaN on SiC HEMTs. Recent advances in compound semiconductor epitaxial growth that directly influence device performance will also be discussed. These include tight control of thickness, composition, and doping levels across all die necessary for HEMTs, reduction of RF losses especially for GaN on Si, and migration to larger wafer sizes.
Due to their physical and electronic properties the wide band gap (WBG) materials Silicon Carbide and Gallium Nitride show great potential for power semiconductor devices. With the capability to operate at higher switching speeds and higher temperatures, compared to Si devices, the WBG devices offer performance benefits within certain applications such as Electric and Hybrid Vehicles (EV/HV). Manufacturing of these devices presents challenges as the materials are highly stable, plasma processing is required to pattern the materials in order to manufacture the devices. This presentation will provide a review of how plasma etching and deposition is used to enable certain device structures. Advanced techniques such as Atomic Layer Etching (ALE) of GaN gate recess and Atomic Layer Deposition (ALD) of Al2O3 for gate dielectrics on GaN HEMTs will be shown.
Keywords – SiC, Silicon Carbide, GaN, Gallium Nitride, Power semiconductor, HEMT, ALD, plasma etch, plasma deposition
Dr. Ajit Paranjpe has been CTO at Veeco since 2011. He oversees Veeco’s technical innovation and organic growth initiatives in areas such as 5G RF and power GaN, photonics, micro-LED, MRAM and advanced packaging.
Dr. Paranjpe has over 25 years of experience in the semiconductor capital equipment industry and previously served in senior technology development and management roles at Media Lario, Therma-Wave, TORREX, CVC and Texas Instruments. He has broad expertise related to the fabrication of semiconductor, opto-electronic and magnetic thin film devices. He has also co-authored over 40 publications and holds more than 50 patents issued in the U.S. and worldwide.
Dr. Paranjpe holds a Bachelor of Technology in Mechanical Engineering from the Indian Institute of Technology and both a Master of Science in Engineering and Doctor of Philosophy from Stanford University, USA.
The miniaturization led advances in microelectronics over 50 years have revolutionized our lives through fast computing and communication. Recent advances in the field are propelled through More than Moore technologies by applications such as robotics, wearable systems, and healthcare etc. Often these applications require electronics to conform to 3D surfaces and this calls for new methods to realize devices and circuits on unconventional substrates such as plastics and paper. This talk will present various approaches (over different time and dimension scales) for obtaining distributed electronics and sensing components on flexible and conformable substrates, especially in context with tactile or electronic skin (e-skin). These approaches range from distributed off-the-shelf electronics, integrated on flexible printed circuit boards to advanced alternatives such as e-skin by printed nanowires, graphene and ultra-thin chips, etc. This talk will also discuss how the technology for sensitive flexible electronic systems is also the key enabler for mobile health and non-invasive health monitoring etc.
Heterostructures based on layers of atomic crystals have a number of properties often unique and very different from those of their individual constituents and of their three dimensional counterparts. The combinations of such crystals in stacks can be used to design the functionalities of such heterostructures. I will show how Raman spectroscopy can be used to fingerprint such heterosctructures, and how these can be exploited in novel light emitting devices, such as single photon emitters, and tuneable light emitting diodes.
Heterostructures based on layers of atomic crystals have a number of properties often unique and very different from those of their individual constituents and of their three dimensional counterparts. The combinations of such crystals in stacks can be used to design the functionalities of such heterostructures. I will show how Raman spectroscopy can be used to fingerprint such heterosctructures, and how these can be exploited in novel light emitting devices, such as single photon emitters, and tuneable light emitting diodes.
MEMS is almost as old as microelectronic transistors. Furthermore, the MEMS community has also been promising similar results as that of microelectronic community of low cost devices. In the microelectronics world, very large scale integration (VLSI) of transistors has led to over a billion devices per chip with significant processing, storage and transmission functionality. However, in the MEMS world, we are still stuck with one or few devices per chip, with the aim to improve the sensitivity, functionality, manufacturability and often size of single or few devices per chip or die. This philosophy of “one design, one fab and one product” will never lead to reduced cost and hence our devices will be good in lab, but impractical in market. We are making nanoscale chips, but the electrical contacts have not shrunk. This means we are wasting significant fabrication area per chip as well. We generally do not like more than one M/NEMS device per chip due to fear of coupling and undesirable parasitic effects. However, we can use these undesirable behaviours to provide for mechanical multiplexing between a large number of sensors on a single chip. In this presentation, I will present recent results of mechanically multiplexing upto 20 sensors on a single M/NEMS chip, along with mathematical techniques and applications of such devices showing promise of VLSI of M/NEMS.
Bhaskar Choubey holds the chair of analogue circuit in University of Siegen. Prior to his current position, he was an associate professor in Oxford University in UK and lecturer in Glasgow University, UK. He received his doctorate from Oxford as a Rhodes scholar. He serves as an associate editor of IEEE Sensors Journal and has served as an AE of IEEE TCAS-II in past. He has been awarded the IEEE Sensors Council early career achievement GOLD award and the Myril B Reed best paper award in IEEE MWSCAS. His research interests are in analogue circuits, image sensors, nonlinear dynamics and M/NEMS.
The interest in 2D layered materials has been renovated with the successful isolation of single- and few-layer graphene in 2004 and the elucidation of its outstanding electronic properties. Since then, the research on graphene and other atomic-films has been exponentially increased and new interesting phenomena and applications were demonstrated. The intense study of the growth mechanism of graphene has enabled today the growth of millimeter-size single-crystal and single-layer graphene domains, a very important milestone towards integration in new and existing technologies. This was achieved by understanding the basic processes taking place during the growth. While he ability to synthesize large-area and high quality atomic films is a prerequisite for their successful integration into a wide variety of applications, little is known about the growth mechanism of other 2D materials.
In this talk, I will describe our attempts to achieve large-scale synthesis of 2D materials in general with emphasis on transition metal dichalcogenides (TMD). I will start by reviewing current methodologies for the synthesis of TMD films, with emphasis on chemical vapor deposition, due to its proven record with graphene and other 2D materials. Then I will cover our modifications to such methodologies in order to achieve better homogeneity and control, including the use of volatile precursors and the development of a seeded-growth approach. Beside planar films, the formation of 3D structures, few-layer graphene/TMD heterostructures, will be discussed, from the synthetic and applications point of view.
Dr. Ariel Ismach holds a BEng in Materials Engineering from Ben Gurion University of the Negev, and an MA and PhD in Materials and Interfaces from the Faculty of Chemistry, Weizmann Institute. He was awarded a prize from the Israel Chemistry Society for his doctoral thesis. In 2009 he moved to Berkeley for a post-doctoral position at the Department of Electrical Engineering, University of California–Berkeley and the Materials Science Division of the Lawrence Berkeley Laboratory. In 2011 he joined the group of Prof. Ruoff in the department of Mechanical Engineering, at the University of Texas in Austin, where he leaded a small group of Ph.D. students and postdocs researching the growth and characterization of various 2D materials. He joined the Materials Science and Engineering department at Tel Aviv University in October 2014 where he had established a laboratory dedicated to study the growth and properties of 2D atomic-crystals. His group is working to address basic scientific questions regarding the formation and the structure-property relationship of 2D materials as well as developing new methodologies to engineer such layered materials and their heterostructures for applications in catalysis, energy storage and photovoltaics.
Ravinder Dahiya is Professor of Electronics and Nanoengineering and Engineering and Physical Sciences Research Council (EPSRC) Fellow in the School of Engineering at University of Glasgow. He is the Director of Electronic Systems Design Centre (ESDC) and the leader of Bendable Electronics and Sensing Technologies (BEST) group. His group conducts fundamental research on high-mobility materials based flexible electronics and electronic skin, and their application in robotics, prosthetics and wearable systems.
Prof. Dahiya has published more than 200 research articles, 4 books (3 at various publication stages), and 12 patents (including 7 submitted). He has given more than 100 invited/plenary talks. He has led many international projects including those funded by European Commission, EPSRC, The Royal Society, The Royal Academy of Engineering, and The Scottish Funding Council.
He is Distinguished Lecturer of IEEE Sensors Council and is on the Editorial Boards of Scientific Reports (Nature Group), IEEE Transactions on Robotics and IEEE Sensors Journal. He was the Technical Program Co-Chair (TPC) for IEEE Sensors Conference in 2017 and in continuing in this role for the IEEE Sensors Conference in 2018.
Prof. Dahiya holds EPSRC Fellowship and in past he received Marie Curie Fellowship and Japanese Monbusho Fellowship. He has received several awards and most recent among them are: 2016 IEEE Sensor Council Technical Achievement Award, the 2016 Microelectronic Engineering Young Investigator Award (Elsevier). In 2016, he was included in list of Scottish 40UNDER40.
Photosensors responsive to the short wavelength infrared (SWIR, wavelength range of 1 um to 2.5 um) radiation are used in a variety of applications including environmental monitoring and medical diagnosis. However, conventional SWIR sensors are limited by complex die transfer and bonding processing. Hence our goal is to advance SWIR photodiodes and phototransistors by using a new generation of narrow bandgap conjugated polymers that are processed by solution-processing techniques and allow simple direct deposition. The polymers show photoresponse up to wavelength of 1.7 micron. We develop a physical model to pinpoint the origins of efficiency losses by decoupling the exciton dissociation efficiency and charge collection efficiency, and identify avenues that will improve sensor detectivity. We will compare the metrics of photodiodes to phototransistors in terms of response time, external quantum efficiency, and dark current noise. Lastly we show the various potential applications of organic SWIR devices including spectroscopic identification and image reconstruction.
Dr. Tse Nga Tina Ng is an Associate Professor in the Department of Electrical and Computer Engineering at University of California San Diego (UCSD), USA. She received her PhD in Physical Chemistry under the supervision of Professor John Marohn at Cornell University. Subsequently she worked at Palo Alto Research Center before joining UCSD in 2015. Her work on printed systems has received the 2012 Innovation Award from Flextech Alliance, named Runner-up for the Wall Street Journal Technology Innovation Award, received second place in the 2017 Bell Lab Prize, and named the Hartwell Investigator in 2017. She is a member of the External Advisory Board for Partnership for Research and Education in Materials (PREM) and is on the Editorial Board of the journal Flexible Printed Electronics.
Recent developments in integrated photonics has enabled basic building blocks for a CMOS-compatible all integrated on-chip optical coherence tomography (OCT) based imaging system. These devices include, among other things, on-chip lasers, detectors, modulators, interferometers, couplers, and lenses. The prospect of ‘on-chip’ OCT has particular relevance for diagnosis of early stages of Chronic Obstructive Pulmonary Disease (COPD), one of the major global health problems. The combination of high resolution offered by OCT, along with low cost of mass-fabrication in a CMOS foundry implies it can be a panacea for application in the developing world, where the installation and maintenance cost of high resolution imaging techniques such as x-ray CT-scan is a serious limiting factor. Here, we propose delivering such an on- chip OCT device via standard bronchoscope, identifying the major requirements of such a device for early stage diagnosis and progress monitoring of COPD, and determining the major advantages and limitations of such approach.
Ashim Dhakal is co-founder and chief scientist at Phutung Research Institute in Kathmandu, Nepal, a pioneer institute of science and technology research in Nepal. He received European Union’s prestigious Erasmus Mundus scholarship and obtained MSc degree in Photonics Engineering jointly from Ghent University, Free University Brussels, University of St. Andrews, Herriot-Watt University. He received PhD degree from Ghent University in 2016, and has since been actively involved in biophotonics research. His research interest include silicon and silicon nitride photonics, spectroscopy, and optical coherence tomography. He has over 40 international publications with an h-index of 11, and is grantee of UK’s EPSRC grant.
Prof. Francesca Iacopi has 20 years’ industrial and academic expertise in Materials for Semiconductor Technologies, with over 120 peer-reviewed publications and 9 granted US patents. Her research emphasis is on the translation of basic scientific advances in nanomaterials and novel device concepts into semiconductor technologies. She was recipient of an MRS Gold Graduate Student Award (2003), an ARC Future Fellowship (2012), and a Global Innovation Award in Washington DC (2014). Francesca is a Fellow of the Institution of Engineers Australia and Senior Member of IEEE. She is currently Head of Discipline, Communications and Electronics, in the Faculty of Engineering and IT of the University of Technology Sydney.
I am going to discuss about the ever-evolving advances in organic thin-film based devices, which have fueled many of the developments in the field of flexible and stretchable electronics. After the discovery of conducting polymers, the question arose as to whether organic materials would also find applications as organic semiconductors. Today, owing to the constant improvements of the particular properties of molecular materials – organic semiconductors have made their way for the fabrication of devices, which are flexible and stretchable in nature. There have been substantial development and optimization over many decades on the growth of these materials on hard and flexible substrates as thin-films and fabrication devices with different functionalities by exploiting their easily tunable electronic properties (e.g. organic field-effect transistors, OFETs). In this talk, I am going to present some of the latest developments in our group on the fabrication of OFET based flexible sensors, which are found to be suitable as affordable healthcare solutions. This includes flexible sensors for continuous monitoring body temperature to detect various health complicacies, such as sleep apnea, febrile seizure for newborn babies or monitoring body temperature patients with poor thermoregulation. We are on the process of developing internet-of-things medical devices (IoT-MD) for more accurate predication of health conditions.
Prof. Dipak Kumar Goswami is professor in Physics in Indian Institute of Technology Kharagpur (IIT Kharagpur). Prof. Goswami completed his Ph.D degree from Institute of Physics, Bhubaneswar in 2004. Afterwards, he worked in Norwestern University, Advanced Photon Source, USA and Max Planck Institute for Metals Research, Stuttgart, Germany for three years. His areas of interests are growth of thin films, nanostructures and fabrication of various organic electronic devices. He has published about 50 research articles including national and international journals. Some of the works were published in very high impact journals, like, Science, Physical Review Letters, and Journal of American Chemical Society etc.
Silicon Photonics – Past and Future In less than two decades silicon photonics has evolved from a research curiosity to an industry-relevant field with products in the marketplace. Silicon photonics takes advantage of the maturity and existing manufacturing infrastructure of the silicon CMOS world to implement photonic functions, including wavelength-selective functions, high speed modulators or detectors, fiber-coupling structures, sensing structures etc. The key business driver for silicon photonics is the high speed optical transceiver for short-reach interconnect with aggregate data rates of 100 Gb/s and higher. However increasingly other products are emerging, on one hand in highend telecom products and on the other hand in a variety of sensing applications. This plenary paper will review the evolution that the field has gone through and will then focus on new exciting developments with major scientific or application impact.
There is a significant need to build efficient non-von Neumann computing systems for highly data-centric artificial intelligence related applications. Brain-inspired computing is one such approach that shows significant promise. Memory is expected to play a key role in this form of computing and in particular, phase-change memory (PCM), arguably the most advanced emerging non-volatile memory technology. Brain-inspired computing is likely to be realized in multiple levels of inspiration given a lack of comprehensive understanding of the working principles of the brain. In the first level of inspiration, the idea would be to build computing units where memory and processing co-exist in some form. Computational memory is an example where the physical attributes and state dynamics of memory devices are exploited to perform certain computational tasks in place with very high areal and energy efficiency. In a second level of brain-inspired computing using PCM devices, one could design a co-processor comprising multiple cross-bar arrays of PCM devices to accelerate training of deep neural networks. PCM technology could also play a key role in the space of specialized computing substrates for spiking neural networks and this can be viewed as the third level of brain-inspired computing using these devices
We describe a platform able to harness the properties of graphene on silicon wafers in a transfer -free and site -selective fashion. The electrical characteristics of the graphene fall remarkably in line with those of the more established epitaxial graphene on the expensive SiC wafers. This platform offers a pathway for implementation of graphene at the wafer -level, and could greatly benefit further miniaturization, in particular More-than-Moore integration.
Dr. Omkaram (Om) Nalamasu is senior vice president and chief technology officer (CTO) of Applied Materials, Inc. He brings extensive experience and passion to the role of CTO, where he leads the development of disruptive products to address new markets and businesses in partnership with the broader technology ecosystem. Dr. Nalamasu has built a world-class team to support Applied’s leadership in materials engineering. He also serves as president of Applied Ventures, LLC, the venture capital fund of Applied Materials, where he oversees strategic investments in early- and growth-stage companies.
A world-renowned expert in materials science and one of our industry’s most respected forward-thinkers, Dr. Nalamasu has championed a renewed focus on Applied’s global innovation culture through various internal development programs and open innovation methods. He has solidified strategic relationships with universities, government organizations and research institutes around the world.
Dr. Nalamasu joined Applied in 2006 after serving as an NYSTAR Distinguished Professor of materials science and engineering at Rensselaer Polytechnic Institute, where he also served as vice president of research. He has held key research and development leadership positions at AT&T Bell Laboratories, Bell Laboratories/Lucent Technologies, and Agere Systems, Inc., and was director of Bell Laboratories’ Nanofabrication Research Laboratory, MEMS and Waveguides Research, and Condensed Matter Physics organizations.
His research interests include nanomanufacturing, nanopatterning, electronic and photonic materials, and lithography, with special emphasis on applying patterning and materials expertise for device fabrication for electronics, photonics and energy applications.
Dr. Nalamasu has made seminal contributions to the fields of optical lithography and polymeric materials science and technology. He has received numerous awards, authored more than 180 papers, review articles and books, and holds more than 120 worldwide issued patents.
In 2017, Dr. Nalamasu was elected to the U.S. National Academy of Engineering for technical innovation spanning materials development, atomically controlled thin-film fabrication, and commercialization in microelectronics and energy generation and storage. He is a member of the board of directors of The Tech Museum in Silicon Valley and serves on several national and international advisory boards. He received his Ph.D. from the University of British Columbia, Vancouver, Canada.
Ferroelectric HfO2-based thin films are extensively studied as they show promise for low power devices such as negative capacitance ferroelectric field-effect transistors with reduced sub-threshold slope for logic and memory applications. However, the polycrystalline nanostructure with extended grain boundaries is a potential source of irreproducibility and reliability issues for the electrical performances of the devices. On the other hand, epitaxial ferroelectric perovskites present some flaws such as a high dielectric constant leading to a large depolarization field in thin films and large leakage currents dues to grain boundary conduction paths.
In this presentation, we propose to use a composite material consisting of amorphous and nanocrystalline BaTiO3 as a ferroelectric gate oxide in metal-oxide semiconductor capacitors. The dielectric permittivity, leakage currents, and memory window will be discussed on the basis of macroscopic current-voltage measurements as well as local investigations by scanning probe microscopy in different electrical modes. We will show that this composite can be integrated into TiN-gated capacitors that exhibit ferroelectric behavior, together with a medium effective permittivity and low leakage currents. Prospect for future nanoelectronic devices will be discussed.
Catherine Dubourdieu is a Full Professor at Freie Universität Berlin and the Head of the Institute “Functional oxides for energy efficient information technology” at the Helmholtz-Zentrum Berlin. She earned an Engineer diploma from Grenoble Institute of Technology in 1992 and a MSc and PhD degrees in Physics from Grenoble University in 1992 and 1995 respectively. After a postdoctoral fellowship at Stevens Institute of Technology, USA, she held a permanent position at the Centre National de la Recherche Scientifique, France, from 1997 to 2016. From 2009 to 2012, she was a Visiting Scientist at the IBM T.J. Watson Research Center, USA. She is a senior member of the IEEE Society and a member of the Executive Committee of the European Materials Research Society.
Jayasimha Atulasimha*
Mechanical and Nuclear Engineering & Electrical and Computer Engineering
Virginia Commonwealth University.
We have demonstrated that voltage induced strain and acoustic waves can switch the magnetization of nanomagnets [1-3] and soft layer of a microscale magnetic tunnel junction (MTJ) [4]. This talk will discuss the above experimental work with complementary modeling that accounts for defects and thermal noise to study the switching error in such “straintronic” devices based on magnetostrictive nanomagnets and their potential to scale to non-volatile memory devices with < 50nm lateral dimensions. We will also explore the suitability of such strain switched nanomagnets to Non-Boolean computing [5].
Further, recent work shows that direct voltage control of magnetic anisotropy (VCMA) in conjunction with magnetic skyrmion states [6, 7] offer a robust mechanism for switching nanomagnets. Our simulations show that inclusion of Dzyaloshinskii-Moriya Interaction (DMI) to force such reversal through a specific (skyrmion) state could be more robust to both thermal noise and defects than precessional VCMA switching schemes [7]. Such a skyrmion’s core also oscillates resonantly with the input voltage induced VCMA and can be exploited for implementing unique neuromorphic functionalities such as a “resonate and fire neuron” in an energy efficient manner [8]. Preliminary experiments in this direction will also be presented.
Acknowledgements:
* The strain control of magnetism research was performed in J. Atulasimha’s group at VCU (N. D’Souza, M. Salehi Fashami, M. M. Al-Rashid, D. Bhattacharya) in collaboration with S. Bandyopadhyay group at VCU (A. Biswas, H. Ahmad, M. A. Abeed), G. P. Carman group (UCLA), J. P. Wang group (U. of Minnesota) and B. Kirby, A. Grutter and D. B. Gopman (NIST); and its application to non-Boolean/neuromorphic compu