Article
Materials Science, Multidisciplinary
Carmine Borelli, Alessio Bosio, Antonella Parisini, Maura Pavesi, Salvatore Vantaggio, Roberto Fornari
Summary: The electrical and optical properties of high-resistivity kappa-Ga2O3 epitaxial films are studied, and their performance as solar-blind photodetectors is investigated. The photodetectors exhibit a high rejection ratio, reproducible on-off switching times, and significant photo-gain. The material shows non-critical growth conditions, intrinsic spectral selectivity, and good UV-detection performance, making it suitable for solar-blind ultraviolet photodetectors.
MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Jie Zhang, Fengjing Liu, Dong Liu, Yanxue Yin, Mingxu Wang, Zixu Sa, Li Sun, Xiaoxin Zheng, Xinming Zhuang, Zengtao Lv, Wenxiang Mu, Zhitai Jia, Yang Tan, Feng Chen, Zai-xing Yang
Summary: The study investigates the photodetection performance of thin amorphous Ga2O3 nanosheet, which has been widely used as dielectric and passivation materials. By peeling off from the Ga solid-melt surface, the amorphous Ga2O3 nanosheet is confirmed to have an amorphous characteristic through selected area electron diffraction and X-ray diffraction. However, due to limited absorption ability and abundant defect states, the amorphous Ga2O3 nanosheet shows low photocurrent and slow response time even at a bias voltage. To enhance the photodetection performance, PbI2 nanosheet is grown on the surface of the amorphous Ga2O3 nanosheet, forming a Ga2O3/PbI2 heterojunction photodetector. The heterojunction photodetector exhibits larger photocurrent (1.6 nA) and faster response times (2 ms rise time and 3 ms decay time) even at a zero bias voltage, and it also shows excellent self-powered photoresponse characteristic and mechanical flexibility when configured into a flexible photodetector. This work provides a pathway for the development of high-performance flexible optoelectronic devices.
MATERIALS TODAY PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Zeyulin Zhang, Yanshuang Ba, Dazheng Chen, Pengru Yan, Qingwen Song, Yuming Zhang, Weidong Zhu, Chunfu Zhang, Yue Hao
Summary: In this study, ultrawide-bandgap Ga2O3 was introduced into an inorganic perovskite device, significantly enhancing its performance in the deep UV region.
APPLIED SCIENCES-BASEL
(2023)
Article
Nanoscience & Nanotechnology
Huawei Lin, Qin Su, Ruixi Mao, Qian Cheng, Deliang Zhu, Shun Han, Ming Fang, Wenjun Liu, Peijiang Cao, Youming Lu, Dnyandeo Pawar
Summary: A super-high-performance self-powered ultraviolet photodetector, based on p-GaN/a-Ga2O3 p-n heterojunction, was fabricated by growing nanoscale-thick films of n-type a-Ga2O3 on p-type GaN film using magnetron sputtering at room temperature. This device exhibited a self-powered effect and dual-band UV detection capability, showing exceptional photodetection performance.
ACS APPLIED NANO MATERIALS
(2023)
Article
Chemistry, Physical
Shan Li, Yusong Zhi, Chao Lu, Chao Wu, Zuyong Yan, Zeng Liu, Jian Yang, Xulong Chu, Daoyou Guo, Peigang Li, Zhenping Wu, Weihua Tang
Summary: The paper presents a broadband ultraviolet self-powered photodetector based on a beta-Ga2O3/CuI heterostructure, demonstrating excellent performance under UVC light and remarkable stability. Insights into the intrinsic physical behaviors of the device are investigated through energy band diagrams and first principle calculations.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Nanoscience & Nanotechnology
Hardhyan Sheoran, Shi Fang, Fangzhou Liang, Zhe Huang, Shuchi Kaushik, Nethala Manikanthababu, Xiaolong Zhao, Haiding Sun, Rajendra Singh, Shibing Long
Summary: This article reports on the fabrication of high-performance deep ultraviolet photodetectors (DUV PDs) on metal-organic chemical vapor deposition (MOCVD)-grown beta-Ga2O3 heteroepitaxy. The fabricated DUV PDs exhibit stable operation at high temperature, with an ultralow dark current and a high photo-to dark-current ratio. These DUV PDs show high detection sensitivity and potential for solar-blind detection applications.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Engineering, Electrical & Electronic
Guo-Liang Ma, Ang Gao, Zeng Liu, Wei-Ming Sun, Shan Li, Zu-Yong Yan, Wei-Yu Jiang, Bing-Yang Sun, Xiao-Hui Qi, Pei-Gang Li, Wei-Hua Tang
Summary: In this study, a self-powered deep ultraviolet photodetector based on Ga2O3/BFO heterojunction was fabricated, showing excellent deep UV signal detection ability and potential for self-powered deep UV photodetection applications.
IEEE SENSORS JOURNAL
(2021)
Article
Physics, Applied
Betul Ceviz Sakar, Zeynep Orhan, Fatma Yildirim, S. Aydogan
Summary: Se-doped CdO thin films were prepared on p-Si substrates via spin coating. Morphological, structural, and absorption measurements were performed. The CdO:Se/p-Si heterojunction exhibited good rectification feature in the dark and under different illumination conditions. It showed high responsivity and stability, indicating its potential application in photodetection.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2023)
Article
Engineering, Electrical & Electronic
Xu Cao, Yanhui Xing, Jun Han, Junshuai Li, Tao He, Xiaodong Zhang, Jiahao Zhao, Baoshun Zhang
Summary: Heterogeneous epitaxy of epsilon-Ga2O3 films on c-plane sapphire was conducted by metal-organic chemical vapor deposition method. The effects of thickness on crystal quality and morphology of epsilon-Ga2O3 films were analyzed. A high-quality epsilon-Ga2O3 film with good optical properties was obtained.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2021)
Article
Nanoscience & Nanotechnology
Xi Zhu, Yutong Wu, Guowei Li, Kun Zhang, Shuanglong Feng, Wenqiang Lu
Summary: Ti3C2Tx with 2D structure was prepared by hydrothermal method. A Ga2O3-Ti3C2Tx heterojunction was formed by van der Waals interaction between 1D nanowires and 2D nanosheets, which improved the performance of photodetectors by enhancing the transfer of photoelectrons.
ACS APPLIED NANO MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Mohamed S. Mandi, Husam S. Al-Arab, A. Hmood, M. Bououdina
Summary: The research investigates the influence of substrate nature on the characteristics of tin monosulfide films, showing that the substrate plays a critical role in determining the structure, morphology, and photoresponse of the films. The results demonstrate significant differences in performance and properties of the photodetectors based on different substrates, highlighting the importance of substrate selection in thin film fabrication.
Article
Materials Science, Multidisciplinary
Yingying Cheng, Jiaxing Mao, Hongyi Zhu, Yanhui Dong, Jian Chen, Mingkai Li, Yinmei Lu, Yunbin He
Summary: In this study, a strategy for constructing Ga2O3/BFMO heterojunction-based photodetectors was proposed to enhance responsivity and detectivity by utilizing the built-in electric field and ferroelectric depolarization electric field for carrier separation. The fabricated photodetector exhibited tunable performance under zero bias, with higher performance observed in the upward poling state and under weak light illumination.
JOURNAL OF MATERIALS CHEMISTRY C
(2023)
Article
Nanoscience & Nanotechnology
Jinho Bae, Ji-Hyeon Park, Dae-Woo Jeon, Jihyun Kim
Summary: A compact self-powered solar-blind UV-C photodiode was demonstrated using an ultra-wide bandgap alpha-Ga2O3 thin film as a wavelength-selective absorber layer, eliminating the need for low-performance and bulky solar blind UV bandpass filters. The photodetector exhibited excellent responsivity, fast rise/decay characteristics, and solar blindness, making it a promising candidate for the development of a compact and energy-independent next-generation UV-C photodetector.
Article
Chemistry, Physical
Sang Ha Jeong, Thi Kim Oanh Vu, Eun Kyu Kim
Summary: Si-doped Ga2O3 photodetectors were studied with different annealing temperatures, showing that devices annealed at 500 degrees C had the highest photoresponsivity and external quantum efficiency, while devices annealed at 800 degrees C had the fastest switching speeds. These results are attributed to changes in defect densities from chemical bond formation between Si and O atoms.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Engineering, Electrical & Electronic
B. Hanna, Lekshmi R. Pillai, Kavya Rajeev, K. P. Surendran, K. N. N. Unni
Summary: We fabricated and characterized UV photodetectors using thin films of polymer/ZnO nanocomposites. By studying different polymers and varying the ZnO content, we found that the P(VDF-TrFE)/ZnO nanocomposite with a ferroelectric property exhibited the best performance. The choice of top electrode material also played a significant role in the device performance.
SENSORS AND ACTUATORS A-PHYSICAL
(2022)
Article
Physics, Applied
Junao Cheng, Scott Poehler, Masihhur Laskar, Lu Ma, Santhakumar Kannappan, Siddharth Rajan, Yiying Wu, Wu Lu
Summary: This study investigates the carrier transport mechanisms in chemical vapor deposited few-layer MoS2 at different temperatures using a two-terminal device configuration. The results reveal a transition in transport behavior from resonant tunneling to hopping, and eventually to band transport as the temperature increases. These findings are significant for understanding the material properties of future 2D semiconductor devices.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2022)
Article
Chemistry, Physical
Christopher Kang, Nicholas P. Bauman, Sriram Krishnamoorthy, Karol Kowalski
Summary: This article discusses the performance and applicability of QPESIM, a new simulation of the QPE algorithm designed to take advantage of modest computational resources. It demonstrates the versatility of QPESIM in simulating various electronic states by examining the ground and core-level states of H2O. Additionally, it shows that QPE simulations using 15 active orbitals significantly reduce errors in core-level excitation energies compared to earlier simulations with smaller active spaces.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2022)
Article
Crystallography
Jani Jesenovec, Benjamin L. Dutton, Cassandra Remple, Natalie Smith-Gray, Magesh Murugesan, Carl Peterson, Brooke K. Downing, Sriram Krishnamoorthy, Matthew D. McCluskey, John S. McCloy
Summary: This study investigates the properties of alloyed beta-Ga2O3 material and finds that Sc2O3 alloying can increase the bandgap, but the electrical conductivity is similar to the non-doped material.
JOURNAL OF CRYSTAL GROWTH
(2022)
Article
Materials Science, Multidisciplinary
Jacqueline Cooke, Praneeth Ranga, Jani Jesenovec, Arkka Bhattacharyya, Xueling Cheng, Yunshan Wang, John S. McCloy, Sriram Krishnamoorthy, Michael A. Scarpulla, Berardi Sensale-Rodriguez
Summary: This study utilizes spectral analysis and PL microscopy to investigate various micrometer-scale extended defects in 13-Ga2O3 and 13-(Al,Ga)2O3 materials. The defects include pits, divots, mounds, etc. The combined use of PL microscopy with AFM and SEM provides detailed characterization of these defects.
OPTICAL MATERIALS EXPRESS
(2022)
Article
Nanoscience & Nanotechnology
Esmat Farzana, Arkka Bhattacharyya, Nolan S. Hendricks, Takeki Itoh, Sriram Krishnamoorthy, James S. Speck
Summary: This study presents the use of oxidized-metal contacts and high-kappa dielectric field plate to improve the performance of vertical beta-Ga2O3 Schottky diodes. These modifications enhance the reverse blocking capability, reduce edge leakage current, and enable lower power dissipation, making them promising for high-power applications.
Article
Nanoscience & Nanotechnology
Yiwen Song, Arkka Bhattacharyya, Anwarul Karim, Daniel Shoemaker, Hsien-Lien Huang, Saurav Roy, Craig McGray, Jacob H. Leach, Jinwoo Hwang, Sriram Krishnamoorthy, Sukwon Choi
Summary: Ultra-wide band gap semiconductor devices based on fi-phase gallium oxide (Ga2O3) offer higher switching performance, efficiency, and lower manufacturing cost compared to current wide band gap power electronics. However, overheating remains the major challenge for the commercialization of Ga2O3 electronics, affecting device performance and reliability. By fabricating a Ga2O3/4H-SiC composite wafer and implementing a low-temperature epitaxy and device processing scheme, we achieved high thermal performance and a power figure of merit of 300 MW/cm2 in Ga2O3 devices, the highest reported thus far. Thermally optimized Ga2O3/diamond composite wafers with reduced Ga2O3 thickness and thinner bonding interlayers show potential for further reduction in device thermal impedance.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Engineering, Electrical & Electronic
Rujun Sun, Arkka Bhattacharyya, Muad Saleh, Sriram Krishnamoorthy, Michael A. A. Scarpulla
Summary: We studied defect properties of ALD-grown SiO2/beta-Ga2O3 MOS capacitors using C-V, UV-assisted C-V, and DLTS techniques. The defect properties were investigated on (100), (010), and (-201) orientations with and without remote O-2 plasma exposure before SiO2 deposition. Minor differences in types and total interface state densities were observed among these orientations. However, remote O-2 plasma exposure significantly increased the densities of initially empty fast charge states for all orientations. Mobile charges were detected at room temperature and 400 K, indicating surface damage caused by even remote O-2 plasma exposure.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Materials Science, Coatings & Films
Jacqueline Cooke, Praneeth Ranga, Arkka Bhattacharyya, Xueling Cheng, Yunshan Wang, Sriram Krishnamoorthy, Michael A. Scarpulla, Berardi Sensale-Rodriguez
Summary: We report the discovery of a new type of structural defect in beta-Ga2O3 homoepitaxial thin films, which we call sympetalous defects. These defects consist of a line defect in the substrate combined with a multi-faceted inverted polycrystalline pyramid in the epitaxial film. Photoluminescence microscopy revealed polarization-dependent luminescence and circular dichroism at these defects. Understanding and controlling these defects is important for modifying film properties, affecting device yields, and influencing characterization experiments.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2023)
Article
Physics, Applied
Nidhin Kurian Kalarickal, Ashok Dheenan, Joe. F. F. McGlone, Sushovan Dhara, Mark Brenner, Steven. A. A. Ringel, Siddharth Rajan
Summary: We presented the design and fabrication of beta-Ga2O3 self-aligned lateral MOSFETs with a heavily doped beta-Ga2O3 cap layer. The fabricated device achieved a record high DC drain current density of 560 mA/mm at 5V drain bias, although the current density was limited by excessive self-heating. However, pulsed I-V measurements showed a record high current density of 895 mA/mm and a high transconductance of 43 mS/mm, indicating reduced self-heating in the device. These findings are promising for the development of high power density devices based on beta-Ga2O3.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Applied
Agnes Maneesha Dominic Merwin Xavier, Arnob Ghosh, Sheikh Ifatur Rahman, Andrew Allerman, Shamsul Arafin, Siddharth Rajan
Summary: Ultra-violet light emitting diodes emitting at 339 nm with transparent interband tunnel junctions were achieved using plasma-assisted molecular beam epitaxy. By utilizing compositionally graded n and p-type layers, a low voltage drop at the tunnel junction was obtained, leading to enhanced hole density and tunneling rates. The transparent tunnel junction-based UV LED exhibited a voltage drop of 5.55 V at 20 A/cm(2) and an on-wafer external quantum efficiency of 1.02% at 80 A/cm(2).
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Applied
Saurav Roy, Arkka Bhattacharyya, Carl Peterson, Sriram Krishnamoorthy
Summary: We present a vertical beta-Ga2O3 Schottky barrier diode with a field plate oxide of BaTiO3, which exhibits a breakdown voltage of 2.1 kV. The high breakdown voltage is achieved by using a thick drift layer of 11 μm with a low effective doping concentration. The introduction of a high-k dielectric with a dielectric constant of 248 significantly improves the breakdown voltage without impacting the on-state performance. Analysis of the diode dimensions reveals a uniform distribution of breakdown voltages for the field-plated SBDs. Power losses in both on and off states are analyzed and compared to non-field-plated devices, and the switching losses are estimated analytically.
APPLIED PHYSICS LETTERS
(2023)
Article
Nanoscience & Nanotechnology
Arkka Bhattacharyya, Carl Peterson, Takeki Itoh, Saurav Roy, Jacqueline Cooke, Steve Rebollo, Praneeth Ranga, Berardi Sensale-Rodriguez, Sriram Krishnamoorthy
Summary: We demonstrate a new substrate cleaning and buffer growth scheme in beta-Ga2O3 epitaxial thin films using MOVPE. By growing a low-temperature un-doped Ga2O3 buffer followed by a transition layer to high-temperature Si-doped Ga2O3 channel layers, continuous growth of the channel structure was achieved. The parasitic Si channel at the epilayer-substrate interface was effectively compensated through solvent cleaning and hydrofluoric acid treatment. This substrate cleaning combined with the LT buffer scheme shows the potential for designing Si-doped beta-Ga2O3 channels with exceptional transport properties.
Article
Physics, Applied
Esmat Farzana, Saurav Roy, Nolan S. Hendricks, Sriram Krishnamoorthy, James S. Speck
Summary: In this study, PtOx/thin Pt Schottky contacts combined with a high permittivity dielectric (ZrO2) field-plate were used for Schottky barrier engineering in high-voltage vertical beta-Ga2O3 diodes. The results showed that the PtOx/thin Pt/beta-Ga2O3 contact exhibited improved reverse blocking performance and lower turn-on voltage compared to plain metal Pt/beta-Ga2O3 Schottky diodes and plain oxidized metal PtOx/beta-Ga2O3 diodes. Furthermore, the implementation of a high permittivity dielectric field-plate assisted in edge-field management and enabled a higher breakdown voltage. These findings suggest that the PtOx/thin Pt/beta-Ga2O3 Schottky contact, combined with a high permittivity field-plate, has the potential for enabling high-performance and efficient vertical beta-Ga2O3 power switches.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Physical
Erdal Mutlu, Ajay Panyala, Nitin Gawande, Abhishek Bagusetty, Jeffrey Glabe, Jinsung Kim, Karol Kowalski, Nicholas P. Bauman, Bo Peng, Himadri Pathak, Jiri Brabec, Sriram Krishnamoorthy
Summary: This paper presents the TAMM framework for productive and scalable development of computational chemistry methods. By decoupling computation specifications from execution, TAMM allows domain scientists to focus on algorithmic requirements while optimizing performance on various computing systems. The modular structure of TAMM supports different hardware architectures and incorporates new algorithmic advances.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Computer Science, Theory & Methods
Ang Li, Samuel Stein, Sriram Krishnamoorthy, James Ang
Summary: This article proposes a low-level benchmark suite called QASMBench, which provides insightful evaluation metrics for NISQ devices, QC programming compilers, schedulers, assemblers, and quantum system simulators. It consolidates commonly used quantum routines and kernels from various domains and introduces four circuit metrics to analyze the execution efficiency and error susceptibility. QASMBench can be launched and tested on multiple NISQ platforms.
ACM TRANSACTIONS ON QUANTUM COMPUTING
(2023)
