Article
Engineering, Electrical & Electronic
Dae-Myeong Geum, Seong Kwang Kim, Hyeong-Rak Lim, Juhyuk Park, Jaeyong Jeong, Jae Hoon Han, Won Jun Choi, Hyo-Jin Kim, Sanghyeon Kim
Summary: By systematically investigating the wafer-bonded interfaces of p(+)GaAs/n(+)InGaAs and p(+)InGaAs/n(+)InGaAs, it was found that the latter structure exhibited improved interfacial resistivity. The low-temperature bonding process successfully fabricated bonded interfaces without degrading material quality, suggesting good electrical properties in wafer-bonded structures.
IEEE ELECTRON DEVICE LETTERS
(2021)
Article
Chemistry, Physical
Wanglong Wu, Chuankai Liu, Lixiang Han, Xiaozhou Wang, Jingbo Li
Summary: We have developed a novel high sensitive ultraviolet (UV) photodetector based on AlGaN/n-GaN/p-GaN heterostructure high electron mobility transistor (HEMT) on sapphire substrates. The photodetectors demonstrate ultra-low dark current and high light on/off ratio under UV LED irradiation. They also exhibit high photoresponse speed and overall high performance in terms of photoresponsivity, EQE, detectivity, and stability. The proposed photodetectors have the potential for applications in UV communication, Internet of Things, and medical treatment.
APPLIED SURFACE SCIENCE
(2023)
Article
Engineering, Electrical & Electronic
Abdullah Ozkartal, Dheyab Thaer Noori
Summary: In this study, p-NiO/n-GaAs heterojunctions were fabricated using the thermal evaporation method, and the optical and electrical properties of NiO thin films were investigated under illumination and in the dark. The NiO/GaAs contacts exhibited good rectifier and photodiode properties.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2021)
Article
Chemistry, Physical
R. Szymon, E. Zielony, A. Lysak, M. A. Pietrzyk
Summary: In this study, a pair of heterojunctions with different types of interlayer, n-ZnO/ZnCdO and n-ZnCdO/ZnO, were grown and investigated. The electrical properties and parameters of these heterojunctions were characterized using current-voltage (I-V) characteristics and capacitance-voltage characteristics. Different carrier transport mechanisms were observed, including tunneling, multi-tunneling capture-emission, and space-charge limited currents. Defects in the junctions were characterized using deep level transient spectroscopy, and the influence of cadmium ions in the ZnCdO interlayer on trap levels was observed. The interlayer type was found to affect junction parameters and current transport mechanisms. (c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Engineering, Electrical & Electronic
L. Konczewicz, E. Litwin-Staszewska, M. Zajac, H. Turski, M. Bockowski, D. Schiavon, M. Chlipala, M. Iwinska, P. Nita, S. Juillaguet, S. Contreras
Summary: This paper presents a comparative study of electron transport phenomena in heavily doped n-type gallium nitride above the Mott transition with silicon and germanium. The samples were grown using molecular beam epitaxy, metal-organic vapor phase epitaxy, and halide vapor phase epitaxy. The temperature dependence of resistivity and Hall Effect was measured from 10 K to 650 K. The study of the electrical transport properties at sub-room temperatures provides valuable insights into extrinsic material properties and scattering mechanisms. The limitations of the applied models are also discussed.
SEMICONDUCTOR SCIENCE AND TECHNOLOGY
(2022)
Article
Chemistry, Physical
Zhiming Liang, Hyun Ho Choi, Xuyi Luo, Tuo Liu, Ashkan Abtahi, Uma Shantini Ramasamy, J. Andrew Hitron, Kyle N. Baustert, Jacob L. Hempel, Alex M. Boehm, Armin Ansary, Douglas R. Strachan, Jianguo Mei, Chad Risko, Vitaly Podzorov, Kenneth R. Graham
Summary: It has been shown through Seebeck coefficient and Hall effect measurements that mobile electrons play a significant role in charge-carrier transport in p-conjugated polymers heavily p-doped with strong electron acceptors. Doping with oxidizing agents eliminates the transport gap at high doping concentrations, indicating a promising route to high-performance n-type organic thermoelectric materials.
Article
Materials Science, Multidisciplinary
J. Y. Kim, M. Samiepour, E. Jackson, J. Ryu, D. Iizasa, T. Saito, M. Kohda, J. Nitta, H. E. Beere, D. A. Ritchie, A. Hirohata
Summary: In this work, the fabrication of a Fe/n-GaAs spin injection device and the experimental setup for optical gating of the nonlocal spin transport signal were demonstrated. The results showed more uniform current distribution at the Fe/n-GaAs injector interface at bias voltages higher than the Schottky barrier height. Successful spin injection into n-GaAs was confirmed through three- and four-terminal Hanle measurements, with strong interfacial spin dephasing at high magnetic fields. Using a time-resolved pump-probe Kerr rotation setup, a modulation of the nonlocal signal (0.4 +/- 0.3)% depending on the light helicity was observed in Fe/n-GaAs lateral spin injection devices at 30 K.
Article
Chemistry, Multidisciplinary
Qinglin Wang, Yu Yao, Xianhe Sang, Liangrui Zou, Shunhao Ge, Xueting Wang, Dong Zhang, Qingru Wang, Huawei Zhou, Jianchao Fan, Dandan Sang
Summary: The n-type Ce:ZnO (NL)/p-type BDD heterojunction prepared using hydrothermal method shows enhanced photoluminescence intensity and blue shift of the UV emission peak compared with the undoped heterojunction. The heterojunction devices exhibit good thermal stability and rectification characteristics at different temperatures.
Article
Biochemistry & Molecular Biology
Yu Yao, Dandan Sang, Liangrui Zou, Dong Zhang, Qingru Wang, Xueting Wang, Liying Wang, Jie Yin, Jianchao Fan, Qinglin Wang
Summary: The hydrothermal approach was used to fabricate a heterojunction of n-Al:ZnO nanorods/p-BDD, which showed increased photoluminescence intensity and a blue shift of the UV emission peak compared to the n-ZnO NRs/p-BDD heterojunction.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2022)
Article
Chemistry, Physical
Veaceslav Sprincean, Liviu Leontie, Iuliana Caraman, Dumitru Untila, Mihaela Girtan, Silviu Gurlui, Petru Lisnic, Corneliu Doroftei, Aurelian Carlescu, Felicia Iacomi, Mihail Caraman
Summary: This study investigates the optical characteristics of micrometer-sized flexible InSe/In2O3 heterojunctions and suggests their potential for optoelectronic applications.
Article
Engineering, Electrical & Electronic
Jincheng Mei, Yi Li, Junyi Yan, Jiaqing Zhuang, Xingping Wang, Xin Zhang, Yuda Wu, Mengdi Zou, Chuang Peng, Wenyan Dai, Zhen Yuan, Ke Lin
Summary: The optoelectronic and structural properties of the n-V2O5/p-GaAs heterojunction were investigated, and it was found that the device performance is closely related to the annealing temperature and annealing time during the film preparation. The volt-ampere characteristic curves of the junction were thoroughly investigated under different temperature and illumination conditions. The responsivity of the n-V2O5/p-GaAs heterojunction was 0.00517 A/W at 1550 nm, with detectivity values of 1.15 x 10(7) Jones and 4.75 x 10(8) Jones at 0 and 3 V bias, respectively. These results are significant for the exploration and improvement of near-infrared optoelectronic devices based on V2O5.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2022)
Article
Chemistry, Multidisciplinary
Bogdan R. R. Borodin, Prokhor A. A. Alekseev, Vladislav Khayrudinov, Evgeniy Ubyivovk, Yury Berdnikov, Nickolay Sibirev, Harri Lipsanen
Summary: Control over doping at the nanoscale during nanostructure growth is crucial for device fabrication. This study investigates the p (Zn)- and n (Sn)- doping distributions and the formation of 3D p-n junctions in planar GaAs nanowires grown on doped GaAs substrates. Various techniques, including scanning electron microscopy, transmission electron microscopy, and conductive atomic force microscopy, are used to analyze the nanowire morphology and doping distribution. The results show that bipolar transistor-like lateral nanostructures can be formed during p-n or n-p growth on misoriented (001) GaAs substrates, while core-shell field effect transistor-like structures can be synthesized on singular (001) substrates. The effects of substrate misorientation on 3D doping distribution are attributed to the preferential incorporation of dopants in polar side facets compared to a non-polar top (001) facet.
Article
Chemistry, Physical
Yurui Han, Yuefei Wang, Danyang Xia, Shihao Fu, Chong Gao, Jiangang Ma, Haiyang Xu, Bingsheng Li, Aidong Shen, Yichun Liu
Summary: This work presents a high-detectivity solar-blind deep ultraviolet photodetector with a fast response speed, based on a nitrogen-doped graphene/beta Ga2O3/GaN p-i-n heterojunction. The heterojunction exhibits enhanced self-powered solar blind detection ability and has a photoresponsivity of 8.3 A W-1 with a high I-light/I-dark ratio of over 10^6 and a detectivity of approximately 9 x 10^14 Jones. The excellent performance of the device is attributed to the continuous conduction band, larger built-in potential, and enhanced built-in electric field in the beta Ga2O3.
Article
Chemistry, Multidisciplinary
Ligang Ma, Xiaoqian Ai, Yujie Chen, Pengpeng Liu, Chao Lin, Kehong Lu, Wenjun Jiang, Jiaen Wu, Xiang Song
Summary: In this study, ZnO/NiO nanocomposites were successfully fabricated by constructing pn heterojunction. The nanocomposites exhibited excellent photocatalytic activity at 550 degrees C. The results showed that the heterojunction interface between n-type ZnO and p-type NiO played a crucial role in impeding the recombination of photogenerated electron-hole pairs and improving photocatalytic efficiency.
Article
Engineering, Electrical & Electronic
Nattakorn Borwornpornmetee, Rawiwan Chaleawpong, Peerasil Charoenyuenyao, Adison Nopparuchikun, Boonchoat Paosawatyanyong, Phongsaphak Sittimart, Tsuyoshi Yoshitake, Nathaporn Promros
Summary: In this study, the electrochemical characteristics of Al/n-NC FeSi2/p-Si/Pd heterostructures were investigated using impedance spectroscopy. The results showed that the values of resistance and constant phase element in the equivalent circuit of the heterostructures changed with biased voltage. The real permittivity values varied at different frequencies, and the loss tangent was high, indicating leakage in the device. The alternating conductivities started at low frequencies and exponentially increased as the frequency increased. The direct current conductivity also varied with biased voltage.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2022)
Article
Materials Science, Coatings & Films
Hugh J. Bullen, Suresh Vishwanath, Rambert K. Nahm, H. Grace Xing, James R. Engstrom
Summary: In this study, the nucleation and growth of WSe2 thin films on HOPG were investigated under ultrahigh vacuum conditions. The study revealed the influence of temperature on the film composition and morphology. Examine the effects of extinguishing one of the species (W or Se) on the growth process, which provides insights into the growth mechanism.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2022)
Article
Nanoscience & Nanotechnology
Reet Chaudhuri, Zexuan Zhang, Huili Grace Xing, Debdeep Jena
Summary: By introducing indium in the GaN channel, the piezoelectric polarization difference across the heterointerface can be tuned, resulting in ultra-high carrier densities. These high-density InGaN/AlN 2DHGs have high mobilities at room temperature and do not freeze out at low temperatures.
ADVANCED ELECTRONIC MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
Gustavo Alvarez-Escalante, Ryan Page, Renjiu Hu, Huili Grace Xing, Debdeep Jena, Zhiting Tian
Summary: This study systematically investigates the thermal conductivity and thermal boundary conductance of homoepitaxial AlN thin films, revealing that both parameters increase with the film thickness. The homoepitaxially grown AlN exhibits high thermal conductivity and ultrahigh thermal boundary conductance, showing promising potential for efficient heat dissipation and device design.
Article
Nanoscience & Nanotechnology
Len van Deurzen, Ryan Page, Vladimir Protasenko, Kazuki Nomoto, Huili (Grace) Xing, Debdeep Jena
Summary: This study demonstrates the existence of multimode lasing at sub-300 nm wavelengths through optical pumping in AlGaN heterostructures. The fabricated AlGaN lasers exhibit promising performance at room temperature.
Article
Nanoscience & Nanotechnology
John G. Wright, Celesta S. Chang, David A. Muller, Huili G. Xing, Debdeep Jena
Summary: We investigate the structural and electronic properties of NbN/GaN junctions grown by plasma-assisted molecular beam epitaxy. High-quality NbN films grown on GaN exhibit superconductivity with critical temperatures above 10 K, even at thicknesses as low as 3 nm. We find that the NbN lattice follows the stacking sequence of the underlying GaN, with domain boundaries occurring at the atomic steps on the GaN surface. Through Schottky barrier diode measurements, we determine the barrier height of the NbN/GaN junction to be 1.3 eV.
Article
Physics, Applied
Wenwen Zhao, Mohammad Javad Asadi, Lei Li, Reet Chaudhuri, Kazuki Nomoto, Huili Grace Xing, James C. M. Hwang, Debdeep Jena
Summary: This study demonstrates the suspended AlN thin-film bulk acoustic resonators (FBARs) at 9.2 GHz in the X-band, showing promising performance and potential for integration with other devices for RF front end and microwave filter applications in quantum computing.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Physics, Applied
Zexuan Zhang, Jimy Encomendero, Eungkyun Kim, Jashan Singhal, YongJin Cho, Kazuki Nomoto, Masato Toita, Huili Grace Xing, Debdeep Jena
Summary: The study revealed the presence of high-density 2D electron gas in Al(Ga)N/GaN heterojunctions, and achieved low sheet resistance in N-polar undoped pseudomorphic GaN/AlGaN structures. These results provide important insights for the development of high-power RF electronics based on N-polar III-nitride high electron mobility transistors.
APPLIED PHYSICS LETTERS
(2022)
Article
Nanoscience & Nanotechnology
Jashan Singhal, Jimy Encomendero, Yongjin Cho, Len van Deurzen, Zexuan Zhang, Kazuki Nomoto, Masato Toita, Huili Grace Xing, Debdeep Jena
Summary: In this study, N-polar AlN epilayers were successfully grown on the N-face of AlN substrates using plasma-assisted molecular beam epitaxy. In situ thermal deoxidation and Al-assisted thermal desorption were used to remove native surface oxides and impurities, resulting in successful homoepitaxy. The grown AlN layer exhibited smooth surface morphologies and low structural defect densities, with the presence of interesting inversion domains.
Article
Multidisciplinary Sciences
Zexuan Zhang, Yusuke Hayashi, Tetsuya Tohei, Akira Sakai, Vladimir Protasenko, Jashan Singhal, Hideto Miyake, Huili Grace Xing, Debdeep Jena, YongJin Cho
Summary: Successful homoepitaxial growth of N-polar AlN has been achieved on large-area N-polar AlN templates using MBE. Al-assisted cleaning enables the epitaxial film to maintain N-polarity, resulting in a smooth, defect-free surface and suppression of nonradiative recombination centers.
Article
Physics, Applied
Shubham Jadhav, Ved Gund, Benyamin Davaji, Debdeep Jena, Huili (Grace) Xing, Amit Lal
Summary: This paper demonstrates a HZO-based ferroelectric NEMS unimorph as a fundamental building block for low-energy capacitive readout in-memory computing. The reported device achieves analog programmable control of the piezoelectric coefficient, demonstrating linear behavior and high computational throughput.
APPLIED PHYSICS LETTERS
(2022)
Article
Physics, Applied
Micah S. S. Haseman, Daram N. N. Ramdin, Wenshen Li, Kazuki Nomoto, Debdeep Jena, Huili Grace Xing, Leonard J. J. Brillson
Summary: This study investigates the movement of electrically charged defects in Ga2O3 vertical trench power diodes using cathodoluminescence point spectra and hyperspectral imaging. The researchers observed the spatial rearrangement of optically active defects under strong reverse bias. These findings demonstrate the potential impact of extreme electric fields on atomic rearrangement and local doping changes in beta-Ga2O3, highlighting the importance of nanoscale device geometry in other high-power semiconductor devices.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Physics, Applied
Zexuan Zhang, Jashan Singhal, Shivali Agrawal, Eungkyun Kim, Vladimir Protasenko, Masato Toita, Huili Grace Xing, Debdeep Jena
Summary: Polarization-induced carriers are important for achieving high electrical conductivity in ultrawide bandgap semiconductor AlGaN. However, studies on these carriers in N-polar AlGaN are rare. This study observes and characterizes polarization-induced two-dimensional electron gases (2DEGs) in N-polar AlGaN/AlN heterostructures with varying Al content. The results provide valuable insights for designing high electron mobility transistors and UV photonic devices.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Applied
Jashan Singhal, Eungkyun Kim, Austin Hickman, Reet Chaudhuri, Yongjin Cho, Huili Grace Xing, Debdeep Jena
Summary: We conducted a study on the compositional dependence of electrical characteristics in AlxGa1-xN quantum well channel-based AlN/AlGaN/AlN high electron mobility transistors (HEMTs), with x values of 0.25, 0.44, and 0.58. The use of selectively regrown n-type GaN Ohmic contacts resulted in increased contact resistance with higher Al content in the channel. The DC HEMT device characteristics showed a progressive reduction in maximum drain current densities and a simultaneous decrease in threshold voltage with increasing x values.
APPLIED PHYSICS LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Wenwen Zhao, Mohammad Javad Asadi, Lei Li, Reet Chaudhuri, Kazuki Nomoto, Huili Grace Xing, James C. M. Hwang, Debdeep Jena
Summary: This study demonstrates epitaxial AlN thin-film bulk acoustic resonators (FBARs) on SiC substrates with first-order thickness extensional modes of 15-17 GHz. The achieved quality factor Q(max) of approximately 443, electromechanical coupling coefficient k(eff)(2) of approximately 2.3%, and f center dot Q of approximately 6.65 THz figure of merit are among the highest in the Ku-band (12-18 GHz). The clean primary mode with a high quality factor allows these epitaxial AlN FBARs to be used in Ku-band acoustic filters with clean bands and steep rejection. Additionally, their compatibility with AlN/GaN/AlN quantum well high-electron-mobility transistors (QW HEMTs) allows for monolithic integration with HEMT low noise amplifiers (LNAs) and power amplifiers (PAs).
IEEE ELECTRON DEVICE LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Gustavo A. Alvarez, Joseph Casamento, Len van Deurzen, Md Irfan Khan, Kamruzzaman Khan, Eugene Jeong, Elaheh Ahmadi, Huili Grace Xing, Debdeep Jena, Zhiting Tian
Summary: Aluminum scandium nitride (AlScN) is gaining attention for its larger piezoelectric response compared to AlN, but alloying Sc with AlN reduces thermal conductivity. Self-heating limits power handling in AlScN devices, and we compared thermal conductivity of AlScN grown on different substrates.
MATERIALS RESEARCH LETTERS
(2023)
