Workshop on Emerging Trends in Semiconductor Technology

Kemper E. Lewis, PhD, MBA, and dean of UB’s School of Engineering and Applied Sciences, is a global leader in engineering design, system optimization and advanced manufacturing. Prior to being named dean, Lewis served as chair of UB's Department of Mechanical and Aerospace Engineering, where he was also the Moog Professor of Innovation.

Lewis is also the director of UB’s Community of Excellence in Sustainable Manufacturing and Advanced Robotic Technologies (SMART), an initiative that harnesses the strengths of faculty across the university to develop advanced manufacturing and design processes including autonomy, intelligence and materials technologies.

He is a Fellow of the American Society of Mechanical Engineers (ASME), and has served on the National Academies Panel on Benchmarking the Research Competitiveness of the United States in Mechanical Engineering. He has published over 200 refereed journal articles and conference proceedings and has been principal or co-principal investigator on grants totaling more than $33 million.

Active in the profession, Lewis chaired ASME’s Mechanical Engineering Department Head Executive Committee. He has received numerous awards in recognition of his teaching and research excellence from several professional societies, including ASME, the Society of Automotive Engineers, the American Society for Engineering Education, and the American Institute of Aeronautics and Astronautics.

Lewis joined UB in 1996. He earned a BS in mechanical engineering and a BA in mathematics from Duke University, his MS and PhD in mechanical engineering from Georgia Tech, and an MBA from UB.

Jonathan Bird joined the faculty of the UB Department of Electrical Engineering as Professor in Fall 2004. Prior to this, he obtained his BSc (First-Class Honors) and PhD degrees in Physics from the University of Sussex (United Kingdom), in 1986 and 1990, respectively. He was a JSPS visiting fellow at the University of Tsukuba (Japan) from 1991 - 1992, after which he joined the Frontier Research Program of the Institute of Physical and Chemical Research (RIKEN, also in Japan). In 1997, he was appointed as Associate Professor in the Department of Electrical Engineering at Arizona State University, where he spent seven years before joining UB. Prof. Bird's research is in the area of nanoelectronics. He is the co-author of nearly 300 peer reviewed publications as well as of undergraduate and graduate textbooks.

Venu Govindaraju, VP for Research and Economic Development and SUNY Distinguished Professor, is also the founding director of the Center for Unified Biometrics and Sensors of Computer Science and Engineering at the State University of New York (SUNY) at Buffalo. He received his Bachelor’s degree with honors from the Indian Institute of Technology, Kharagpur in 1986, and his Ph.D. from SUNY Buffalo in 1992.

A recognized authority in the field of Pattern Recognition, Govindaraju has received peer honors such as the IAPR/ICDAR Outstanding Achievements (2015), Distinguished Alumnus Award from IIT Kharagpur (2014), the IEEE Technical Achievement Award (2010), MIT Global Indus Technovator Award (2004), and fellowships from the major professional societies such as AAAS, ACM, IAPR, IEEE, and the SPIE. He is a member of the National Academy of Inventors (2015).

Govindaraju is credited with major conceptual and practical advances in this area with six books and over 425 refereed publications. He has served on the editorial boards of several premier journals including the most prestigious IEEE Transactions on Pattern Analysis and Machine Intelligence and has been the Editor-in-Chief of IEEE Biometrics Council Compendium. Recently he served as the president of the IEEE Biometrics Council positioning it for consideration of a full fledged IEEE Technical Society.

Govindaraju has graduated 37 doctoral students as their major advisor and was recently awarded the University at Buffalo’s “Excellence in Graduate Student Mentoring Award (2017)”. He has given over a hundred invited talks, keynotes, plenaries and seminars, at prestigious venues including influential think tanks such as the Science and Technology Investment committee of the National Academy of Sciences.

Govindaraju has had active and continuous sponsorship from the National Science Foundation for the past 15 years (2002-17) and a career total of nearly $70M of sponsored funding as a Principal or Co-Principal Investigator from several federal and state agencies and industry. His annual research expenditures are consistently over $1.5M, making him a top performer at UB.

Govindaraju is the Chief Research Officer at UB with an annual operating budget of $35M and over 100 staff members reporting to the Office of the Vice President of Research and Economic Development. He sits on the President’s cabinet as well as the Provost’s cabinet and is responsible for managing UB’s research enterprise, including supporting scholarly excellence, creating collaborations, ensuring compliance in a regulatory environment, and oversees programs that contribute to regional job growth and a diversified economy in the Western New York region.

Professor Sellers research focuses on the development and investigation of novel quantum-engineered material and devices for next generation photovoltaics. Specific programs involve hot carrier dynamics in III-V and perovskite systems, defect formation and stability of thin-film CIGS and perovskites solar cells, as well as their suitability for deep space power applications.

Recently, there has been significant interest in renewable energy as an alternative source of power to replace traditional fossil fuels and reduce our dependency on oil. Photovoltaics - the conversion of the sun’s energy to electricity – is an attractive approach since it offers a free and abundant source of clean energy. However, commercial solar cells are currently limited to conversion efficiencies on the order of 30% due to the poor spectral matching of single band gap semiconductors to the Sun’s irradiance. To enable the large-scale implementation of solar cells for utility-scale energy applications improvements in power conversion efficiency and lower system costs must be achieved. To circumvent the fundamental limitations of single energy-gap solar cells, devices based on third generation (3G) processes have been proposed. In this presentation I will introduce such concepts; recent progress in the field, and related research in my group and with collaborators at UB.

Joey Luther is a senior research fellow within the Materials, Chemical, and Computational Science directorate at NREL. He began his research career studying III-V light-emitting diodes and multijunction solar cells at North Carolina State University, and then moved to NREL during his graduate studies to study defects within various photovoltaic technologies. Under the direction of Arthur Nozik, while working on his doctorate through the Colorado School of Mines, he developed solar cells from colloidal nanocrystals, which exploit a phenomenon where multiple excitons are generated and harvested per incident photon. Luther then became a postdoctoral scholar in Paul Alivisatos’ group at the University of California, Berkeley and Lawrence Berkeley National Laboratory. In 2009, he rejoined NREL as a senior research scientist.

Luther’s research interests focus on developing clean energy technologies through the frontiers of nanoscience and low-cost advanced processing. His research is funded by Basic Energy Sciences Energy Frontier Research Centers, the U.S. Department of Energy’s Solar Energy Technologies Office, the U.S. Department of Defense, strategic partnerships with industry, and NASA.

Concepts for Mitigating Thermal-Cycling Fatigue and Improving Radiation Tolerance in Perovskite Photovoltaics

Metal halide perovskites are being explored for many applications including terrestrial photovoltaics (PVs), but also for use in more extreme environments such as space. Two of the major stressors for operation in space include exposure to background radiation and wildly changing temperature conditions. Mechanical residual stresses within multilayer thin-film device stacks become problematic during thermal changes due to differing thermal expansion and contraction of the various layers. Thin-film photovoltaic (PV) devices are a prime example where this is a concern during temperature fluctuations that occur over long deployment lifetimes. In this talk, we show development of perovskite devices that control of the residual stress within halide perovskite thin-film device stacks and understanding of the radiation interactions. For thermal cycling, an additive approach reduces the residual stress and strain to near-zero at room temperature and prevents cracking and delamination during intense and rapid thermal cycling. We demonstrate this concept in both n-i-p (regular) and p-i-n (inverted) unencapsulated perovskite solar cells and minimodules, where both types of solar cells maintained over 80% of their initial PCE after 2,500 thermal cycles in the temperature range of -40°C to 85°C. The mechanism by which stress engineering mitigates thermal cycling fatigue in these perovskite PVs is discussed.

Wanyi Nie is interested in electronic devices for energy conversion, photon sensing and information processing. She focuses on developing novel semiconductors, understanding their physical properties tied to the material structures. Next, her group will find a best way of using the materials. 

Solar to electricity conversion technology is one of the most promising clean energy generation techniques to address the global energy consumption crisis. Lead halide perovskites-based photovoltaics have recently undergone an unprecedented surge in the power conversion efficiency improvements, and are at the edge for commercialization. To implement the perovskite PV technologies in the market, the poor operational stability of the device must be addressed, which remains as a bottleneck.

In this talk, I will discuss our progress in perovskite photovoltaic module development using a simple, additive assisted dip coating method. The additive greatly widens the processing time window allowing for a uniform perovskite film deposition over a large area [1]. As a result, a mini module with power conversion efficiency of 16 % was demonstrated. Next, I will discuss the perovskite solar cell’s operational lifetime under various gas environment. When exposing the solar cell under various gas mixture environment, we observed an interesting device degradation behavior upon constant white light illumination. And the device performance can be restored once the light is removed. And we also discovered that the relative humidity plays a central role in accelerating the device degradation process and recovery effect [2]. Finally, I will discuss the role of the interface in the perovskite solar cells’ operational stability. We found that self-assembled monolayer hole transporting layer as a robust interface that can stabilize the performance.

[1] Huang et al, Joule, 5, 958-974 (2021)

[2] Wenson et al, Journal of Material Chemistry, A, (2022)

Professor Singisetti's research group explores novel electronic devices for high speed circuits, low power logic, and next generation power electronics applications. Please explore more about the research, people and facilities in the group going through the side links, and feel free to contact us if you have any questions about the group.

This first decade of monoclinic Ga2O3 device research has been incredible (underpinned by the availability of large area bulk substrates) in breakdown voltages, power device figure of merit and high-speed performance. It has emerged as a promising ultra-widebandgap semiconductor for next generation power, GHz switching and RF applications. The large bandgap of Ga2O3 leads to a high critical field strength. This high field strength in combination with demonstrated room temperature mobility and calculated electron velocity leads to higher Figures of Merit (BFoM/JFoM) than current commercially available WBG technologies.

This talk will present lateral MOSFETs with improved field plate design and beyond-kV breakdown. Temperature dependent analysis and device simulation suggest an extrinsic breakdown mechanism outside the channel. A simple and yet effective SU-8 polymer passivation technology provides a significant improvement in breakdown voltages. The higher field strength of the SU-8 polymer enables a significant increase in breakdown voltage to 8.5 kV in lateral MOSFETs. We will present the use of ultra-high vacuum annealing techniques to improve the on-resistance of the devices still maintaining the multi-kilo-volt rating of the devices.

Due to its high JFoM, Ga2O3 is a potential candidate for high power density RF amplifiers. We will also present the performance advancement that can be obtained in RF power performance using Ga2O3 technology. We will present the challenges in the technology and potential solutions. Using aggressive gate lengths and gate-source spacing scaling, (AlxGa1-x)2O3/Ga2O3 heterostructure FETs were fabricated that show record high RF performance. Recently, thin channel MOSFETs with deep-sub-micron gate lengths and source/drain regrowth have demonstrated devices with simultaneously low on resistance, high frequency, high voltages. I will conclude the talk with discussion on the challenges that need to be addressed before this technology can be used in the field.

Rongming Chu is a professor in the School of Electrical Engineering and Computer Science in Penn State University’s College of Engineering. His research focuses on electronic materials and devices; integrated circuits and systems; and power and energy systems. 

This talk presents our recent learnings about implementing the super-heterojunction, in place of the conventional field-plate structure, in GaN electronics devices. It covers a few questions we have been trying to answer: (1) can super-heterojunction extend breakdown voltage; (2) what is limiting the breakdown voltage of GaN super-heterojunction devices; (3) can super-heterojunction mitigate dynamic on-resistance degradation; (4) how low-mobility holes affect the switching transient; (5) can super-heterojunction be scaled to multiple 2DEG channels for improved current density; (6) what are benefits and challenges toward the realization of GaN optoelectronic power IC based on the super-heterojunction technology platform.

Professor Seo's research focuses on the development of next generation flexible electronics and optoelectronics; novel nano/micro fabrication processes for the future flexible and stretchable electronics; development and heterogeneous integration of novel low-dimension or ultra-wide bandgap semiconductors

Diamond has attracted considerable attention due to its excellent electrical, mechanical, and thermal properties, enabling the development of high-performance devices in power electronics, radio-frequency applications, bio-electronics, and quantum electronics. However, despite these attractive properties, diamond has several intrinsic material issues, such as difficulty in n-type doping, limited substrate size, slow growth rate, and incompatibility with heterogeneous integration with other semiconductors. Diamond membranes, which refer to thin, standalone, and transferable formats of single- or poly-crystalline diamonds, have been developed to address these issues.

This presentation covers our recent progress on the synthesis and material properties of various types of diamond membranes, as well as their assembly strategies for diverse applications. Specifically, two different synthesis routes for creating poly-crystalline and single-crystalline diamond membranes will be presented, along with their mechanical, electrical, and thermal properties. Given that these diamond membranes are free-standing and transferable, they can be easily integrated with other semiconductors, metals, or existing circuits and form unique heterostructures. We will discuss several heterostructures, including diamond/Cu, diamond/SiC, and diamond/Ga2O3/Si, as exemplary structures. Finally, we will present several prototype devices based on these diamond membranes.

As dimensions of materials cross over fundamental length scales, new physics emerge. We are interested in understanding fundamental spin and magnetic phenomena in materials at reduced dimensions, such as 2D thin films, 1D nanowires and 0D nanocrystals. We grow these materials using both chemical solution phase synthesis, and physical and chemical vapor deposition techniques. Doping, alloying and heterostructures are exploited to modify the properties of the host materials. We use magnetic, charge transport and magneto-optical probes to study the physical properties of these materials.  Presently, the topics of our research include: studying magnetism in atomically thin layers; developing novel 2D magnets and their heterostructures; developing novel magnetic nanoparticles for biomedical applications such as imaging and magnetic hyperthermia.

We are also interested in the design and development of novel materials for energy applications. Our experimental work is guided by first principles theory and materials informatics. Presently our project is focused on developing chalcogenide perovskites, an emerging class of unconventional ionic

In the first part of my talk, I will provide an overview of the ongoing efforts at Buffalo to develop energy-efficient electronics. This includes work on memristors and oscillators based on oxides, which are essential for neuromorphic computing. Additionally, I will discuss advancements in creating energy-efficient transistors utilizing 2D materials. Our research also explores the potential of 2D magnets and various proximity effects that are promising for spintronics applications. I will then articulate our vision for the future of energy-efficient electronics at UB, emphasizing the importance of our academic, industrial, and international collaborations. By leveraging these multidisciplinary efforts, we aim to be at the forefront of developing cutting-edge, energy-efficient electronic technologies. Towards the end of my talk, I will introduce our latest research on the unconventional anomalous Hall effect in 2D magnets driven by self-intercalation. This phenomenon presents exciting opportunities for unconventional computing applications.

Guo-Xing Miao is an Associate Professor in the Electrical and Computer Engineering Department and is cross-appointed to the Institute for Quantum Computing at the University of Waterloo. Professor Miao's research interests lie in spintronics, which use precise electron spin manipulation for information processing. His work places a strong emphasis on nanodevices established on newly emerging spin platforms, such as synthetic diamonds and topological insulators, where information can be processed coherently on the quantum level, rather than digitally on the classical level. The interwined transport of electrons, spins and ions in solid-state devices establishes the forefront for developing semiconductor compatible materials platforms ready for chip integration.

Iontronics benefits from the controllable motion and detection of ions in electronics devices. We demonstrate an ion-coupled memristive system with solid-state electrolyte lithium phosphorus oxynitride as the ion source and the embedding and releasing of Li ions inside the cathodic like TiOx for volatile conductance responses. The system exhibits synapse-like short-term plasticity behaviour without requiring a forming process beforehand or a compliance current during switching, rendering a natural platform for hardware simulating neuron functionalities. Different short-term pulse-based phenomena, including paired pulse facilitation, post-tetanic potentiation, and spike rate-dependent plasticity were observed with unique self-relaxation characteristics. Based on the voltage excitation period, the timescale of the volatile memory can be tuned. In addition, the volatile analog devices can be configured into non-volatile memory units with multibit storage capabilities after an electroforming process. Therefore, on the same platform, we can configure volatile units as nonlinear dynamic reservoirs for performing neuromorphic training and the non-volatile units as the weight storage layer. These phenomena can be generalized to other ion active systems and can effectively process and update temporal information for reservoir and neuromorphic computing paradigms. We proceed to simulate voice recognition as an example with the variable time scale and a minimal training dataset. We also show their actual BOEL integration on 160 nm CMOS chips as a demonstration of principle.

Huamin Li received his BS degree from the College of Physics and Electronics, Shandong Normal University, Jinan, China, in 2007, his MS degree from the College of Engineering, Sungkyunkwan University (SKKU), Suwon, Korea, in 2010, and his PhD degree in the Department of Nano Science and Technology, SKKU, Suwon, Korea, in 2013. His PhD research focused on 2D electronics and optoelectronics. Subsequently, he worked as a postdoctoral research associate in the Department of Electrical Engineering, University of Notre Dame. His postdoctoral work included the development of low-voltage and steep subthreshold swing (SS) components for beyond-CMOS electronic systems using low-dimensional materials. To date, his research results have been included in one book chapter (2013), published in Nature Communications (2015), Scientific Reports (2014), IEEE Transaction on Electron Devices (2009-2012) etc., presented in IEEE International Electron Devices Meeting (IEDM, 2009, 2011-2013), and filed five US and Korean patents with the collaboration of Samsung Electronics Co., Ltd. In 2012, he received Chinese Government Award for outstanding self-financed students abroad by China Scholarship Council.

With the rise of graphene (Gr) since 2004, two-dimensional (2D) have been extensively explored for energy-efficient nanoelectronics due to their novel charge transport properties compared to conventional three-dimensional (3D) bulk materials. However, there are still challenges and issues for practical implementation of 2D materials. Here from the perspective of interfacial design, we take 2D semiconducting MoS2 as an example to review our recent research of energy-efficient nanoelectronics, ranging from synthesis to device demonstration. First, by functionalizing the growth substrate, we can achieve on-demand selective-growth of 2D MoS2 using chemical vapor deposition (CVD) and the electron mobility can be up to 20 cm2/Vs at room temperature. At the interface between MoS2 and SiO2 substrates, an interfacial tension can be induced due to a mismatch of thermal expansion coefficients, which creates an anisotropy of in-plane charge transport [1, 2] as well as a self-formed nanoscroll structure [3]. Second, at the interface between MoS2 and metal contact, a monolayer h-BN decoration can enable novel manipulation of charge transport through quantum tunneling, in contrast with conventional thermionic emission [3]. The contact resistance can be suppressed by both localized and generalized doping using transition metals [4]. Third, at the interface between MoS2 and other 2D materials, band-to-band Zener tunneling and cold-source charge injection can be enabled, giving rise to a superior transport factor (<60 meV/decade) in field-effect transistor (FET) configurations. These novel charge transport can be utilized to overcome the fundamental limit of “Boltzmann tyranny”, and realize tunnel FETs and cold-source FETs with sub-60-mV/decade subthreshold swings [5-7] or novel anti-ambipolar FETs [8]. Fourth, at the interface between MoS2 and ferroelectric or ionic dielectrics, excellent electrostatic gating leads to a superior body factor (<1), and also improves the energy efficiency for transistor operation [9].  

Reference

1.             H. Li and co-workers, under review by Nature Communication.

2.             H. Li and co-workers, DRC, Ann Arbor, MI, p. 133, 2019.

3.             H. Li and co-workers, Adv. Mater., vol. 32, no. 2002716, 2020.

4.             H. Li and co-workers, Nanoscale, vol. 12, pp. 17253, 2020.

5.             H. Li and co-workers, IEEE IEDM, virtual, p.251, 2020.

6.             H. Li and co-workers, ACS Nano, vol. 15, pp. 5762, 2021.

7.             H. Li and co-workers, ACS Nano, vol. 11, pp. 9143, 2017.

8.             H. Li and co-workers, JVST B, vol. 41, no. 053202, 2023.

9.             H. Li and co-workers, Nano Express, vol. 4, no. 035002, 2023. 

Prof. T. Venkatesan is currently a Professor of Physics and ECE at University of Oklahoma (OU), and Scientific affiliate at NIST Gaithersburg. He is also the founding Director of the Center of Optimal Materials for Emerging Technologies (COMET) at OU. Prior to this he was Director of the Nano Institute at the National University of Singapore (NUSNNI) where he was a Professor of ECE, Physics, MSE and NGS. He wore various hats at Bell Labs and Bellcore before becoming a Professor at University of Maryland.

As the inventor of the pulsed laser deposition (PLD) process, he has over 800 papers and 34 patents and is globally among the top one hundred physicists (ranked at 66 in 2000) in terms of his citations (Over 54,300 with a hirsch Index of 118- Google Scholar). He has graduated over 56 PhDs, 35 Post Docs and over 35 undergraduates. He is also the founder and Chairman of Neocera, and Neocera Magma, companies specializing in PLD and magnetic field imaging systems and co-founder of Blue Wave Semiconductors. He recently helped launch two healthcare companies in Singapore, Cellivate and Breathonix. Close to 12 of the researchers (PhD students and Post Docs) under him have become entrepreneurs starting over 25 different commercial enterprises.

He is a Fellow of the Royal Society (FRS), National Academy of Inventors (USA), Singapore National Academy of Science, Asia-Pacific Artificial Intelligence Academy, World Innovation Foundation, American Physical Society (APS), Materials Research Society (MRS), Academician of the Asia Pacific Academy of Materials, winner of the Bellcore Award of excellence, George E. Pake Prize awarded by APS (2012), Distinguished Lectureship on the Applications of Physics Award- APS (2020), President’s gold medal of the Institute of Physics, Singapore, Guest Professor at Tsinghua University, past member of the Physics Policy Committee (Washington DC), the Board of Visitors at UMD and the Chairman, Forum of Industry and Applications of Physics at APS. He was awarded the outstanding alumnus award from two Indian Institute of Technologies- Kanpur (2015) and Kharagpur (2016), India.

His research interests are in Physics and applications of inorganic films and their heterostructures (oxides in particular). He is interested in the electronic, magnetic, and optical properties of materials and is interested in applying them to the field of memristors (neuromorphic circuits), meta-surfaces, plasmonics, and quantum qubits and sensors. He is also interested in using surfaces to control cellular growth, molecular patterns in breath profile to diagnose diseases and the use of high-resolution mass spectrometers in in-operando catalysis processes.

The world is undergoing a dramatic change due to the advent of AI/ML and its progressive incorporation in just about every aspect of our lives. The energy consumption of AI/ML is daunting and there is a need for more energy efficient ways to incorporate artificial intelligence. Conventional silicon electronics is not a good fit for CMOS as the von Neumann bottleneck imposes a significant energy penalty. Memristor based circuits where the memory and the computation are co-located in the same device is one efficient solution to the problem. We are investigating two approaches to memristors- one based on oxides and the other on a molecular platform. My talk will detail both these approaches and address the progress to date.

Steve May, PhD is a professor of Materials Science and Engineering, having joined the department in 2009. He received a BS in Engineering Science and Mechanics from Penn State University and a PhD in Materials Science and Engineering from Northwestern University. Following his doctorate, he was a postdoctoral researcher at Argonne National Laboratory from 2007-2009 in the Materials Science Division. He has received the NSF CAREER award, an ARO Young Investigator Award, the Ross Coffin Purdy Award from the American Ceramic Society, and the Bradley Stoughton Award for Young Teachers from ASM International. His research focuses on synthesis and characterization of thin films and heterostructures, with an emphasis on magnetic, electronic, and optical properties and the use of scattering techniques to probe interfacial properties.

Complex oxides are enabling materials platforms for electronics due to their ability to host ferroic states and metal-insulator transitions, as well as exhibit ultrawide band gaps. In this talk, I will discuss my group’s activities focused on understanding and controlling electronic and optical properties in epitaxial perovskite oxides, such as CaFeO3, SrFeO3, and SrCoO3-d. Emphasis will be placed on how anionic substitutions, such as conversion of oxides to oxyfluorides through topochemical fluorination, can alter optoelectronic properties and enable new functionality such as spatially patterned metal-insulator transitions. I will also describe results from synchrotron spectroscopy and resonant scattering that provide new insights into the mechanisms behind metal-insulator transitions in ferrites and how metal-oxygen covalency – a key factor in electronic phase transitions in correlated oxides – is modified at interfaces.

Ganapathy's experimental research group studies physical properties of low dimensional condensed matter systems. They use advanced nanofabrication techniques combined with controlled sample growth to design and develop sub-micron devices. These devices will be used to explore microscopic mechanisms that influence and/or dictate the fundamental physical properties at the nanometer scale level.

His group explores electron transport in oxide nanowire FETs, nanotubes, 2D semiconductors, and other atomic layers under extreme physical conditions: ultra low temperatures (10 mK), high magnetic fields (16 T) and a.c. electric fields (~GHz). Some of his physics interests include metal-insulator transitions, noise spectroscopy near phase transitions, superconductor-insulator transition, microwave spectroscopy to study collective phases in 2D materials etc. 

Transition metal oxides exhibit several phase transitions accessible by external parameters such as temperature, voltage, and stress. NbO₂ shows an electric field driven insulator-to-metal transition at room temperature, making it a promising candidate for scalable elements in next-generation, neuromorphic computing applications as artificial neurons, oscillators, selector devices, and memory elements. Electrical transport measurements and ultra-low frequency noise spectroscopy measurements help us to understand the role of electrical domains and Mott correlations in applications of NbO_2. Oscillators (with tunable frequencies up to 5 MHz) based on resistive switching in  NbO₂ are built and the dependence of switching parameters on oscillator frequency across device dimensions, applied voltages, and external parameters such as resistance and capacitance are studied.

Christiana Honsberg joined the electrical engineering faculty in the School of Electrical, Computer and Energy Engineering in 2008. She received her bachelor's, master's and doctoral degrees from University of Delaware in 1986, 1989, and 1992, respectively, all in electrical engineering. Before joining the ASU faculty, Honsberg was an associate professor and director for the high performance solar power program at the University of Delaware. She currently holds one patent in the U.S., Japan, and Europe; three patents are pending.

She is the Vice-Dean, Research of the Faculty of Engineering, the University Research Chair in Photonic Devices for Energy and a Professor at the School of Electrical Engineering and Computer Science with a cross-appointment in the Department of Physics at the University of Ottawa. She received the BSc, MSc, and PhD degrees in physics from the University of Ottawa, Ottawa, Ontario, Canada, in 1996, 1998, and 2002, respectively. She has made pioneering contributions to the experimental physics of quantum dots marked by two landmark papers in Science. She gained extensive experience in the design and fabrication of group III-V semiconductor devices while at the National Research Council Canada, Nortel Networks and then Bookham (now Lumentum). Cost reduction strategies and liaison with remote fabrication facilities strongly feature in her industry experience.

Professor Hinzer joined the University of Ottawa in 2007 where she founded the SUNLAB, the premier Canadian modelling and characterization laboratory for next generation multi-junction solar devices and concentrator systems. Professor Hinzer’s research involves developing new ways to harness the sun’s energy. From 2007 to 2017, she was the Tier II Canada Research Chair in Photonic Nanostructures and Integrated Devices. In 2010, she was the recipient of the Inaugural Canadian Energy Award with industry partner Morgan Solar for the development of more efficient solar panels. In 2015, she received the Ontario Ministry of Research and Innovation Early Researcher Award for her contributions to the fields of photonic devices and photovoltaic systems and in 2016, she was the recipient of the University of Ottawa Young Researcher Award. She is a member of the College of New Scholars, Artists and Scientists of the Royal Society of Canada and an IEEE senior member. Professor Hinzer is the principal investigator of the Natural Sciences and Engineering Research Council of Canada Collaborative Research and Training Experience Program titled “Training in Optoelectronics for Power: from Science and Engineering to Technology” (NSERC CREATE TOP-SET), a multi-disciplinary training program involving three universities and aiming to train over 100 students in seven years.

Professor Hinzer is an editor of the IEEE Journal of Photovoltaics. She has published over 170 refereed papers, trained over 150 highly-qualified personnel and her laboratory has spun-off three Canadian companies in the energy sector. Her research interests include new materials, high efficiency light sources and light detectors, solar cells, solar modules, new electrical grid architectures and voltage converters.

High-efficiency photovoltaics: Energy yield considerations for PV installations and new advances in photonics power

Following a short overview of present technologies [1-2], I will discuss our recent results on energy yield calculations for fixed-tilt, tracked and vertical photovoltaic systems [3-6].  I will present a new method to calculate efficiencies for bifacial systems taking into account spectral albedo.  Using novel metrological instruments, I will demonstrate how spectral effects influence energy yield daily and yearly for high latitudes.  I will present results on the effect of high reflective surfaces on bifacial systems. Photovoltaic devices can be adapted to transfer photonic energy using lasers.  This can be done in free space or using optical fibers.  This technology enables electrification of low-noise continuous current systems.  I will present our recent results on the design and performance of photonic power converters based on GaAs and InP [7-10].  To optimize design of complex multijunction devices, I will present a methodology based on dimensionality reduction algorithms using principal component analysis; I will show how this technique compares to the Beer-Lambert absorption law.

Professor Wodo's research topics include informatics and high performance computing for materials design and manufacturing.

The holy grail of materials science is to establish quantitative process-structure-property relationships (PSP). Defining these relationships is rarely straightforward, mainly due to the mismatch between (micro)structural information observed (e.g., via microscopy or simulations) and the principal degrees of freedom governing the PSP. The mismatch exists because microstructural imaging aims to provide detailed, high-resolution maps, while the purpose of establishing quantitative PSPs is to derive the smallest set of variables/descriptors that explain most of the variability in the data. To close this gap, the microstructural data sets should be first represented in machine-friendly formats and then reduced to meaningful descriptors (or other low-dimensional representation) to establish PSP and accelerate materials design. Recently, data-driven approaches become the integral approach to establishing reliable microstructure-property mappings.

In this talk, we will present various approaches to handling the mismatch using microstructure informatics and machine learning tools. Using the combination of different representations (descriptors, two-point correlation, and autoencoder learned latent space), we explore three questions: Given a few datasets with distinct microstructure annotated with the property of interest: 1) Can a small subset of features be selected to train a robust microstructure-property predictive model? And is this subset agnostic to the choice of feature selection algorithm? 2) Can the addition of expert-identified features improve model performance? 3) Can the generalizable model be trained for independent microstructure datasets (different microstructure types)? The questions are essential for any microstructure-sensitive properties. Still, in this talk, we will utilize the problem of constructing structure-property models for organic photovoltaics applications (OPV) to understand data-driven SP models.

Professor Srabanti Chowdhury, affiliated with the Electrical Engineering department and (by courtesy) Materials Science and Engineering at Stanford University, specializes in the wideband gap (WBG) and ultra-wide bandgap (UWBG) materials and device engineering. Her research focuses on energy-efficient system architecture for power and RF applications, particularly emphasizing thermal management. She earned her M.S. in June 2008 and Ph.D. in December 2010 in Electrical and Computer Engineering from the University of California, Santa Barbara. In recognition of her outstanding work on diamond integration with GaN and SiC, resulting in very low thermal boundary resistances for thermal management, Prof. Chowdhury received the 2023 Technical Excellence Award from the Semiconductor Research Society (SRC).
Her achievements also include the 2020 Alfred P. Sloan Fellowship in Physics and the 2016 Young Scientist Award at the International Symposium on Compound Semiconductors (ISCS). Earlier in her career, she was honored with the DARPA Young Faculty Award, NSF CAREER Award, and AFOSR Young Investigator Program (YIP), all in 2015.
Prof. Chowdhury's significant contributions to the field encompass 6 book chapters, 120 journal papers, 150 conference presentations, and 26 issued patents. Actively engaged in IEEE conference committees, including IRPS and VLSI Symposium, she serves on the executive committee of IEDM. Since 2021, she has been a senior fellow at the Precourt Institute for Energy at Stanford. Notably, she became an IEEE fellow in the batch of 2024 for her contributions to wide bandgap semiconductor devices and technology.

On Extracting Maximum Power Density with Material, Device, and Thermal Innovations

The rapid expansion of electric vehicles, data centers, high-performance chips, solar energy, robotics, drones, and everyday adapters has revitalized interest in power electronics. This talk will explore the significant potential of Wide Bandgap Semiconductor (WBG) devices in enhancing the performance, efficiency, and lifespan of electronic devices. In power conversion, WBGs enable more efficient, compact, and lightweight solutions. Collaboration between circuits and devices is pivotal to turning innovative ideas into practical applications. A key focus of our research is the utilization of avalanche in Gallium Nitride (GaN), which can maximize performance in power electronic devices. Vertical device structures, such as Current Aperture Vertical Electron Transistors (CAVETs), have demonstrated remarkable 10MHz switching capabilities and bidirectional operation. These concepts are paving new paths in Gallium Oxide technology. Our recent work on Vertical Double-diffused MOSFET (VDFET) devices has shown that vertical devices in Gallium Oxide are feasible, promising significant advancements. Additionally, our research has highlighted the benefits of diamond-based material technology for thermal management, which offers further improvements in power density and thermal performance. Through this talk, we will illustrate how WBG devices, combined with advanced thermal management and innovative device architectures, are set to enhance the future of electronics.

Professor Mazumder's research group focuses on understanding the atomic-level structural chemistry using atom probe tomography (APT). The material features the group probes include direct 3D visualization of atoms within the analyzed material structures, accurate stoichiometry, confident detection/quantification of impurity or trace elements, small precipitates within the buried hetero-structures and interfacial roughness/abruptness. The unique strength of the group involves employing machine learning (ML) on APT data to extract patterns and link it to known material features. This enables predicting different materials’ properties beyond the capabilities of conventional APT analysis. The rare combination of APT–ML in the group is helping the materials science community to understand and develop wide range of novel material systems including wide bandgap semiconductors, ceramics, quantum materials and many more.

Ultra-wide bandgap (UWBG) semiconductors are poised to overcome the limitations of silicon technology in high-power and high-temperature applications. Progress in UWBG semiconductor technology hinges on precise material engineering to achieve tailored electrical properties while mitigating defects. A profound understanding of the interplay between structural and chemical features influencing these properties is essential. Atom probe tomography (APT) is a pivotal tool for atomic-scale material analysis, providing magnifications up to 10^6 and enabling continuous 3D elemental characterization. This includes detailed insights into chemical distributions, grain boundaries, interfaces, and dopant profiles.

Our research harnesses APT for atomic-scale material characterization, complemented by cutting-edge material informatics-based data analysis methodologies. These techniques allow us to identify and understand atomic-scale structural and chemical features that impede the performance of UWBG materials. This presentation underscores the critical role of atomic-scale analysis in advancing oxide and nitride-based UWBG semiconductors. By leveraging APT and advanced data analysis, we aim to enhance the efficiency, robustness, and performance of power electronic devices.