A5006650430- Parallel Computing and Optimization Techniques
- Ga2O3 and related materials
- ZnO doping and properties
- Methane Hydrates and Related Phenomena
- GaN-based semiconductor devices and materials
- Distributed and Parallel Computing Systems
- Advanced Data Storage Technologies
- Advanced Photocatalysis Techniques
- Geophysics and Gravity Measurements
- Semiconductor materials and devices
- Distributed systems and fault tolerance
- Cloud Computing and Resource Management
- Electronic and Structural Properties of Oxides
- Interconnection Networks and Systems
- Semiconductor Quantum Structures and Devices
- Radiation Effects in Electronics
- 2D Materials and Applications
- Quantum Computing Algorithms and Architecture
- Advanced Chemical Physics Studies
- Advanced NMR Techniques and Applications
- Algorithms and Data Compression
- Embedded Systems Design Techniques
- Spectroscopy and Quantum Chemical Studies
- Advancements in Semiconductor Devices and Circuit Design
- Tensor decomposition and applications
Sri Ramachandra Institute of Higher Education and Research
2025
University of California, Santa Barbara
2021-2025
Vellore Institute of Technology University
2025
University of Utah
2017-2024
Pacific Northwest National Laboratory
2014-2023
Agnitron Technology (United States)
2023
University of California System
2022
Google (United States)
2021-2022
National Institute for Interdisciplinary Science and Technology
2021
Council of Scientific and Industrial Research
2021
Specialized computational chemistry packages have permanently reshaped the landscape of chemical and materials science by providing tools to support guide experimental efforts for prediction atomistic electronic properties. In this regard, structure played a special role using first-principle-driven methodologies model complex processes. Over past few decades, rapid development computing technologies tremendous increase in power offered unique chance study transformations sophisticated...
We present here a report produced by workshop on ‘Addressing failures in exascale computing’ held Park City, Utah, 4–11 August 2012. The charter of this was to establish common taxonomy about resilience across all the levels computing system, discuss existing knowledge various hardware and software layers an build those results, examining potential solutions from both perspective focusing combined approach. brought together participants with expertise applications, system software, hardware;...
Gallium Oxide has undergone rapid technological maturation over the last decade, pushing it to forefront of ultra-wide band gap semiconductor technologies. Maximizing potential for a new system requires concerted effort by community address technical barriers which limit performance. Due favorable intrinsic material properties gallium oxide, namely, critical field strength, widely tunable conductivity, mobility, and melt-based bulk growth, major targeted application space is power...
Modulation-doped heterostructures are a key enabler for realizing high mobility and better scaling properties performance transistors. We report the realization of modulation-doped two-dimensional electron gas (2DEG) at beta(Al0.2Ga0.8)2O3/ Ga2O3 heterojunction using silicon delta doping. The formation 2DEG was confirmed capacitance voltage measurements. A channel used to realize field-effect transistor. demonstration modulation doping in beta-(Al0.2Ga0.8)2O3/ material system could enable...
Irregular and dynamic parallel applications pose significant challenges to achieving scalable performance on large-scale multicore clusters. These often require ongoing, load balancing in order maintain efficiency. Scalable large clusters is a challenging problem which can be addressed with distributed systems. Work stealing popular approach balancing; however its not well understood. Prior work has largely focused shared memory machines. In this we investigate the design scalability of...
In this report, we demonstrate high spectral responsivity (SR) in MBE grown epitaxial \b{eta}-Ga2O3-based solar blind MSM photodetectors (PD). (-2 0 1)-oriented \b{eta}-Ga2O3 thin film was by plasma-assisted on c-plane sapphire substrates. devices fabricated with Ni/Au contacts an interdigitated geometry were found to exhibit peak SR > 1.5 A/W at 236-240 nm a bias of 4 V UV visible rejection ratio 105. The exhibited very low dark current < 10 nA 20 and showed no persistent photoconductivity...
We report a vertical (001)β-Ga2O3 field-plated(FP) Schottky barrier diode (SBD) with novel extreme permittivity dielectric field oxide. A thin drift layer of 1.7μm was used to enable punch-through (PT) profile and very low differential specific on-resistance (Ron-sp)of 0.32 mΩ-cm2. The plate oxide facilitated the lateral spread electric beyond edge enabled breakdown voltage (Vbr) 687 V. termination efficiency increasesfrom 13.2%for non-field plated structure 61%for high structure. surface...
We report a vertical β-Ga2O3 Schottky barrier diode (SBD) with BaTiO3 as field plate oxide on low doped thick epitaxial layer exhibiting 2.1 kV breakdown voltage. A drift of 11 μm effective doping concentration 8 × 1015 cm–3 is used to achieve high Using the high-k dielectric constant 248, voltage increases from 816 V for non-field-plated SBD 2152 (&gt;2× improvement) field-plated without compromising on-state performance. The dimensions are varied analyze effect edge high-field related...
This work reports the fabrication and characterization of a NiOx/β-Ga2O3 heterojunction diode (HJD) that uses metallic nickel (Ni) target to deposit NiOx layers via reactive RF magnetron sputtering lift-off processing with &gt;3 kV breakdown voltage, ultra-low reverse current leakage under high bias, junction electric field (&gt;3.34 MV/cm). The diodes are fabricated bilayer followed by self-aligned plasma-etching for field-termination on both large (1-mm2) small area (300/100-μm...
GPUs are a class of specialized parallel architectures with tremendous computational power. The new Compute Unified Device Architecture (CUDA) programming model from NVIDIA facilitates general purpose applications on their GPUs. However, manual development high-performance code for is still very challenging. In this paper, number issues addressed towards the goal developing compiler framework automatic parallelization and performance optimization affine loop nests GPGPUs: 1) approach to...
Performance optimization of stencil computations has been widely studied in the literature, since they occur many computationally intensive scientific and engineering applications. Compiler frameworks have also developed that can transform sequential codes for data locality parallelism. However, loop skewing is typically required order to tile along time dimension, resulting load imbalance pipelined parallel execution tiles. In this paper, we develop an approach automatic parallelization...
This paper provides an overview of a program synthesis system for class quantum chemistry computations. These computations are expressible as set tensor contractions and arise in electronic structure modeling. The input to the is high-level specification computation, from which can synthesize high-performance parallel code tailored characteristics target architecture. Several components described, focusing on performance optimization issues that they address.
Layered metal dichalcogenide materials are a family of semiconductors with wide range energy band gaps and properties, potential to open up new areas physics technology applications. However, obtaining high crystal quality thin films over large area remains challenge. Here we show that chemical vapor deposition (CVD) can be used achieve electronic grade single Molybdenum Disulfide (MoS2) the highest mobility reported in CVD grown so far. Growth temperature choice substrate were found...
We report on our investigation of the electrical properties metal/Al2O3/GaN metal-insulator-semiconductor capacitors. determined conduction band offset and interface charge density alumina/GaN by analyzing capacitance-voltage characteristics atomic layer deposited Al2O3 films GaN substrates. The at Al2O3/GaN was calculated to be 2.13 eV, in agreement with theoretical predications. A non-zero field 0.93 MV/cm oxide under flat-band conditions inferred, which we attribute a fixed net positive...
In this letter, we experimentally demonstrate direct correlation between efficiency droop and carrier overflow in InGaN/GaN green light emitting diodes (LEDs). Further, flat external quantum curve up to 400 A/cm2 a plasma assisted molecular beam epitaxy grown N-polar double well LED without electron blocking layers. This is achieved by exploring the superior properties of reverse polarization field N-face polarity, such as effective injection higher potential barriers against mechanism. The...
We report on the design and demonstration of polarization-engineered GaN/InGaN/GaN tunnel junction diodes with high current density low tunneling turn-on voltage. Wentzel–Kramers–Brillouin calculations were used to model junctions narrow band gap InGaN-based barrier layers. N-polar p-GaN/In0.33Ga0.67N/n-GaN heterostructure grown using molecular beam epitaxy. Efficient interband was achieved close zero bias a 118 A/cm2 at reverse 1 V, reaching maximum up 9.2 kA/cm2. These results represent...
We used depth-resolved cathodoluminescence spectroscopy and surface photovoltage to measure the effects of near-surface plasma processing neutron irradiation on native point defects in β-Ga2O3. The sensitivity depth resolution these optical techniques enabled us identify spectral changes associated with removing or creating defects, leading identification one oxygen vacancy-related two gallium energy levels β-Ga2O3 bandgap. combined detection Ga2O3 suggests an avenue for identifying physical...
The computational power provided by many-core graphics processing units (GPUs) has been exploited in many applications. programming techniques currently employed on these GPUs are not sufficient to address problems exhibiting irregular, and unbalanced workload. problem is exacerbated when trying effectively exploit multiple concurrently, which commonly available modern systems. In this paper, we propose a task-based dynamic load-balancing solution for single-and multi-GPU allows load...
We report silicon delta doping in Gallium Oxide (\b{eta}-Ga2O3) grown by plasma assisted molecular beam epitaxy using a shutter pulsing technique. describe growth procedures that can be used to realize high Si incorporation an oxidizing oxygen environment. Delta was thin (12 nm) low-resistance layers with sheet resistance of 320 Ohm/square (mobility 83 cm^2/Vs, integrated charge 2.4x10^14 cm^-2). A single delta-doped carriers employed as channel field effect transistor current ID,MAX =292...
We report (010)-oriented β-Ga2O3 bevel-field-plated mesa Schottky barrier diodes grown by low-pressure chemical vapor deposition (LPCVD) using a solid Ga precursor and O2 SiCl4 sources. with good ideality low reverse leakage were realized on the epitaxial material. Edge termination beveled field plates yielded breakdown voltage of −190 V, maximum vertical electric fields 4.2 MV/cm in center 5.9 at edge estimated, extrinsic RON 3.9 mΩ·cm2 extracted intrinsic 0.023 mΩ·cm2. The reported results...
We report silicon delta-doped β-Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> metal semiconductor field effect transistors (MESFETs) with source-drain ohmic contacts formed by patterned regrowth of n-type Ga . show that regrown can enable a lateral low-resistance contact to the two-dimensional electron gas channel, resistance lower than 1.5 Ω-mm. The fabricated MESFET has peak...
Enhanced interband tunnel injection of holes into a PN junction is demonstrated using P-GaN/InGaN/N-GaN junctions with specific resistivity 1.2 X 10-4 {\Omega} cm2. The design methodology and low-temperature characteristic these discussed, insertion device described. Applications in III-nitride optoelectronics devices are explained energy band diagrams. lower gap polarization fields reduce tunneling barrier, eliminating the need for ohmic contacts to p-type GaN. This demonstration efficient...
In the past few decades, a number of user-level threading and tasking models have been proposed in literature to address shortcomings OS-level threads, primarily with respect cost flexibility. Current state-of-the-art models, however, either are too specific applications or architectures not as powerful flexible. this paper, we present Argobots, lightweight, low-level framework that is designed portable performant substrate for high-level programming runtime systems. Argobots offers...
We report polarization dependent photoluminescence studies on unintentionally-, Mg-, and Ca-doped β-Ga2O3 bulk crystals grown by the Czochralski method. In particular, we observe a wavelength shift of highest-energy UV emission which is pump photon energy polarization. For 240 nm (5.17 eV) excitation almost no observed between E||b E||c, while centroid clearly for 266 (4.66 eV), lying band absorption onsets two polarizations. These results are consistent with originating from transitions...