Article
Physics, Applied
Jun Hyuk Park, Sun-Kyu Hwang, Joonyong Kim, Woochul Jeon, Injun Hwang, Jaejoon Oh, Boram Kim, Younghwan Park, Dong-Chul Shin, Jong-Bong Park, Jongseob Kim
Summary: This study investigates the effect of N2O plasma treatment on the reliability of p-GaN gate AlGaN/GaN HEMTs, specifically in the AlGaN drift region. The results show that N2O plasma treatment can form a GaON/AION compound layer, reduce the number of interface traps, and protect the AIGaN surface, thereby improving the reliability of the device.
APPLIED PHYSICS LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Gunjan Yadav, Sheetal Dewan, Monika Tomar
Summary: In this study, InGaN/GaN quantum well LEDs were fabricated using the Laser MBE technique. The performance of LEDs with conventional and inverted device structures was compared. Room temperature electroluminescence was observed, with a spectral blue shift in the fabricated QW LEDs. The conventional LEDs exhibited higher luminous efficiency, while the inverted LEDs showed lower efficiency droop.
Article
Nanoscience & Nanotechnology
Bruno Cesar da Silva, Adam Biegannski, Christophe Durand, Zahra Sadre Momtaz, Anjali Harikumar, David Cooper, Eva Monroy, Martien Ilse den Hertog
Summary: Ultraviolet GaN photodetectors based on top-down strategies using nanowires (NWs) fabricated through nanosphere lithography and etching techniques demonstrate improved uniformity, morphology, and doping control. Measurements show a linear response of photocurrent to optical power, indicating that the dominant photodetection mechanism is the drift of photogenerated carriers at the junction, with negligible surface effects. These results demonstrate the unique properties of NW-based photodetectors that can be assessed through a scalable and low-cost fabrication process.
ACS APPLIED NANO MATERIALS
(2023)
Article
Physics, Applied
Ece N. Aybeke, Alexandra-Madalina Siladie, Remy Vermeersch, Eric Robin, Oleksandr Synhaivskyi, Bruno Gayral, Julien Pernot, Georges Bremond, Bruno Daudin
Summary: Practical semiconductor nanowire optoelectronic devices require controlling their electrical transport properties. This study quantitatively measured the local carrier density in doped GaN nanowires using scanning spreading resistance microscopy. The results reveal the presence of a conductive shell and resistive core in Mg-doped p-type nanowires, while Si-doped n-type nanowires exhibit a resistive shell and conductive core.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Chemistry, Physical
Jing Wang, Xin Wu, Yizhe Liu, Tian Qin, Kaicheng Zhang, Ning Li, Juan Zhao, Ruquan Ye, Zhanxi Fan, Zhenguo Chi, Zonglong Zhu
Summary: The study introduces a novel small molecular hole-transporting material SFDT-TDM based on spirofluorene-dithiolane, synthesized through easy and cost-effective routes, which shows high efficiency and stability in perovskite solar cells.
ADVANCED ENERGY MATERIALS
(2021)
Article
Energy & Fuels
Zhitao Chang, Jiahao Guo, Qiang Fu, Ting Wang, Rui Wang, Yongsheng Liu
Summary: In this study, two types of dopant-free organic semiconductor materials, ZT-H1 and ZT-H2, were successfully designed and synthesized for use as hole transport materials in perovskite solar cells. ZT-H2 showed improved hole mobility compared to ZT-H1, leading to higher efficiency and stability in the devices. The findings suggest that using a fused central core unit with extended pi-conjugation is an effective strategy for designing dopant-free HTMs for stable and efficient PSCs.
Article
Engineering, Electrical & Electronic
Jinxiao Li, Jian Gao, Xiaohong Yan, Weiran Li, Jian Xu, Qun Wang, Bingxian Ou, Dawei Yan
Summary: High-performance gallium nitride ultraviolet photodetectors were fabricated on homogeneous bulk substrates. However, their performance decreases at high temperatures and the noise characteristics are affected by reverse biases.
SOLID-STATE ELECTRONICS
(2022)
Article
Engineering, Electrical & Electronic
Akash Sachchidanand, Akash Patnaik, Anil Kumar, Pankaj Sharma
Summary: This work investigates the optical performance of lead-free Cs3Sb2Br9-based perovskite solar cells. The n-i-p structure shows better absorption and lower reflection compared to the p-i-n structure. The n-i-p structure exhibits higher generation rate, lower recombination rate, and higher optical current density.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2023)
Article
Engineering, Electrical & Electronic
Dan Zhang, Chaochao Fu, Jing Xu, Chao Zhao, Jianfeng Gao, Yaodong Liu, Menghua Li, Junfeng Li, Wenwu Wang, Dapeng Chen, Tianchun Ye, Dongping Wu, Jun Luo
Summary: This paper discusses the method of using dopant segregation technique to adjust the Schottky barrier heights of NiSi/Si diodes, and presents a technique to distinguish different types of diodes.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2021)
Article
Physics, Applied
Yun Tang, Lei Wang, Xiaowu Cai, Peng Lu, Bo Li
Summary: The radiation effects of a 150 keV proton beam on GaN-based quasi-vertical p-i-n diodes were studied. The increase in radiation-induced defect density resulted in a significant decrease in carrier concentrations and mobilities of P-GaN and N-GaN. Under a proton fluence of 1 x 10(15) p/cm(2), P-GaN transformed into highly resistive N-GaN, causing the p-i-n diodes to lose their PN junction characteristics. Additionally, the contact of P-GaN changed from Ohmic to Schottky contact, and the reverse leakage current mechanism shifted from space-charge-limited current conduction to Ohmic conduction due to a large number of radiation-induced defects in P-GaN and N-GaN.
APPLIED PHYSICS LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Victor Ryzhii, Taichi Otsuji, Maxim Ryzhii, Vladimir Mitin, Michael S. Shur
Summary: The study evaluates the Coulomb carrier drag effect in lateral n+-i-n-n+ graphene devices and analyzes the drag factor affecting the amplification of injected current, along with its dependence on structural parameters, carrier Fermi energy in the n-region, and temperature. Results show that the drag factor reaches its maximum at certain Fermi energy and temperature values, and the parameter determining the current-voltage characteristics shape is also calculated. The findings can be applied for optimizing device structures such as voltage- and current-driven switches, frequency multipliers, and terahertz emitters.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2021)
Article
Physics, Applied
Kai Fu, Ziyi He, Chen Yang, Jingan Zhou, Houqiang Fu, Yuji Zhao
Summary: This study proposes the use of hydrogen plasma treatment to solve the premature breakdown issue in GaN power devices and demonstrates their avalanche capability. The results show that under appropriate process conditions, vertical GaN power devices can achieve avalanche capability. This is an important reference for the future development of efficient and robust GaN power electronics.
APPLIED PHYSICS LETTERS
(2022)
Article
Engineering, Electrical & Electronic
Qianyu Hou, Qing Cai, Qunsi Yang, Pengfei Shao, Danfeng Pan, Dunjun Chen, Hai Lu, Rong Zhang, Youdou Zheng
Summary: In this study, a low-voltage p-i-n GaN-based alpha-particle detector with excellent energy resolution was fabricated. Superior performances were achieved by artificially enlarging the path of alpha particles in the depletion region and utilizing high crystal quality epitaxial film grown on a single-crystal GaN substrate. The results are expected to advance the research of radiation-hardened GaN-based detectors.
IEEE ELECTRON DEVICE LETTERS
(2021)
Article
Physics, Applied
Lin Tian, Francois Sfigakis, Arjun Shetty, Ho-Sung Kim, Nachiket Sherlekar, Sara Hosseini, Man Chun Tam, Brad van Kasteren, Brandon Buonacorsi, Zach Merino, Stephen R. Harrigan, Zbigniew Wasilewski, Jonathan Baugh, Michael E. Reimer
Summary: Dopant-free lateral p-n junctions in the GaAs/AlGaAs material system have potential applications in quantum optoelectronics and ease of integration with other components. However, unwanted charge accumulation at the p-n junction has been a major obstacle. This study introduces a gate voltage protocol that clears the parasitic charge accumulation at low temperature, enabling cryogenic operation of devices and achieving stable, bright, dopant-free lateral p-n junctions.
APPLIED PHYSICS LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Genzhuang Li, Yuan Ren, Wang Lin, Qiliang Wang, Liang He, Liuan Li
Summary: A novel quasi-vertical GaN-on-sapphire MPS diode is fabricated by using the p-NiO/n-GaN heterojunction. The MPS diode exhibits a higher turn-on voltage and on-resistance compared to the Ni-anode SBD. The depletion regions at the heterojunction interface effectively enhance the reverse breakdown voltage.
Article
Physics, Applied
Zhanyong Xing, Haochen Zhang, Yue Sun, Lei Yang, Kunpeng Hu, Kun Liang, Dawei Wang, Houqiang Fu, Haiding Sun
Summary: In this work, an enhancement-mode (E-mode) AlGaN/GaN-based high-electron-mobility transistor (HEMT) with a graded AlGaN cap layer (GACL) is proposed. The GACL is designed to produce high-concentration polarization-induced holes and negative net polarization charges to benefit the normally-OFF operation of the device. The optimized graded-AlGaN-gated metal-semiconductor HEMT achieves a large threshold voltage of 4 V, and shortening the gate length and inserting an oxide layer can suppress gate leakage current and enhance gate voltage swing.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2023)
Article
Engineering, Electrical & Electronic
Xing Wei, Wenchao Shen, Xin Zhou, Wenbo Tang, Yongjian Ma, Tiwei Chen, Dawei Wang, Houqiang Fu, Xiaodong Zhang, Wenkui Lin, Guohao Yu, Yong Cai, Baoshun Zhang
Summary: In this letter, high-performance lateral AlGaN/GaN hybrid anode diodes (HADs) with p-GaN stripe array gate (PSAG) structure are demonstrated, showing much reduced turn-on voltage (V-T) compared with reference p-GaN gate HADs. The PSAG-HADs, without field plates (FPs) or passivation, exhibited a low V-T of 0.8 V, a low reverse leakage current of 1.87 nA/mm at -1 kV, a high I-ON/I-OFF ratio of similar to 10^11, a high breakdown voltage (BV) of 2.69 kV, and a low specific ON-resistance (R-ON,R- sp) of 2.11 mΩ·cm^2. This work demonstrates the promising potential of PSAG-HADs for next-generation high-voltage high-efficiency power electronics.
IEEE ELECTRON DEVICE LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Marco Nicoletto, Alessandro Caria, Carlo De Santi, Matteo Buffolo, Xuanqui Huang, Houqiang Fu, Hong Chen, Yuji Zhao, Gaudenzio Meneghesso, Enrico Zanoni, Matteo Meneghini
Summary: In this article, we extensively investigate the degradation of gallium nitride (GaN)-based high periodicity indium GaN (InGaN)-GaN multiple quantum well (MQW) solar cells under optical stress at high excitation intensity and high temperature. The obtained results suggest that the degradation originates from the diffusion of hydrogen, and the proposed analytical methodology provides insight into MQW solar cell degradation.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Materials Science, Multidisciplinary
Ziyi He, Kai Fu, Mingfei Xu, Jingan Zhou, Tao Li, Yuji Zhao
Summary: A theoretical analysis of the electrical performance of ultrawide-bandgap boron nitride (BN)-based vertical junction devices, including h-BN Schottky diode, h-BN pn diode, and h-BN/AlN pn diode, is performed using technology computer-aided design simulation. This is the first demonstration of BN power devices in simulation. The results show excellent performance for h-BN junctions, especially in breakdown behaviors, providing insights for the future development of robust BN power electronics.
PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS
(2023)
Article
Computer Science, Information Systems
Xiu Zhang, Baoxing Wang, Kai Fu, Rui Yue, Haojie Guo, Shuqi Li, Yong Cai
Summary: This work proposes a novel pulsating DC high-voltage linear driving scheme for GaN-based LED general lighting to save costs and reduce flicker. The superiority and practicality of this scheme in three-phase AC power grids were demonstrated for the first time. Linear driving of GaN LEDs for three-phase AC grids provides superior performance for general lighting, with a 90.7% DC component in the rectified voltage effectively alleviating flicker.
Article
Chemistry, Physical
Yuji Zhao, Mingfei Xu, Xuanqi Huang, Justin Lebeau, Tao Li, Dawei Wang, Houqiang Fu, Kai Fu, Xinqiang Wang, Jingyu Lin, Hongxing Jiang
Summary: III-nitride InGaN material is an ideal candidate for high-performance photovoltaic solar cells, especially in high-temperature applications. This paper provides a comprehensive review of recent developments in InGaN-based solar cells, including theoretical modeling, material epitaxy, device engineering, and high-temperature measurement. Substrate technology and unique properties of InGaN materials, such as polarization control and positive thermal coefficient, are highlighted. Outstanding high-temperature InGaN-based solar cells with quantum efficiency approaching 80% at 450 degrees C have been demonstrated. Future innovations in epitaxy science, device engineering, and integration methods are required to further enhance the efficiency and expand the applications of InGaN-based solar cells.
MATERIALS TODAY ENERGY
(2023)
Article
Physics, Applied
Zheming Wang, Guohao Yu, Xu Yuan, Xuguang Deng, Li Zhang, Shige Dai, Guang Yang, Liguo Zhang, Rongkun Ji, Xiang Kan, Xuan Zhang, Houqiang Fu, Zhongming Zeng, Roy K. -Y. Wong, Yong Cai, Baoshun Zhang
Summary: This study investigated the electrical characterizations of AlGaN/GaN heterojunctions isolated by N implantation at elevated temperatures. Three-terminal measurements were carried out to characterize leakage paths, and crystal lattice damage due to implantation was monitored by high-resolution x-ray diffraction. Compared with room temperature implantation, the current leakage was greatly reduced by the implantation at 300℃. The low leakage was attributed to low acceptor-like energy levels due to low crystal lattice damage by the dynamic annealing effect at high-temperature implantation. The post-annealing process increased the current leakage by two orders of magnitude, suggesting that the implantation isolation process should be conducted after higher temperature processes (> 450℃) in the fabrication of GaN devices. These results can provide valuable information for the fabrication, reliability, and mass production of various GaN-based photonics and electronics.
APPLIED PHYSICS LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Prudhvi Peri, Kai Fu, Houqiang Fu, Jingan Zhou, Yuji Zhao, David J. Smith
Summary: The morphology of GaN substrates grown by HVPE and by ammonothermal methods was observed to have an impact on the performance of GaN-on-GaN p-i-n diodes. HVPE-grown substrates showed ordered surface features, while ammonothermal substrates did not. Diodes fabricated on HVPE substrates had higher reverse-bias voltages compared to those on ammonothermal substrates.
JOURNAL OF ELECTRONIC MATERIALS
(2023)
Article
Materials Science, Coatings & Films
Dinusha Herath Mudiyanselage, Dawei Wang, Houqiang Fu
Summary: In this study, ultrawide bandgap beta-(AlxGa1-x)(2)O-3 vertical Schottky barrier diodes on (010) beta-Ga2O3 substrates were fabricated and demonstrated. The fabricated devices exhibited excellent rectification properties with a high on/off ratio, a low turn-on voltage, and a low on-resistance. The leakage mechanisms of the devices were analyzed and it was found that Poole-Frenkel emission and trap-assisted tunneling were the main mechanisms at high and low temperatures, respectively. This work provides an important reference for the future development of ultrawide bandgap beta-(AlxGa1-x)(2)O-3 power electronics, RF electronics, and ultraviolet photonics.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2023)
Article
Physics, Applied
Chengjie Zhou, Wencheng Niu, Lei Li, Dandan Hao, Hao Huang, Houqiang Fu, Xingqiang Liu, Xuming Zou, Fukai Shan, Zhenyu Yang
Summary: In this study, a multifunctional optoelectronic memory was developed by coupling Au nanoparticles with MoS2, enhancing the light absorption capacity of MoS2 and achieving excellent device performance and storage time. Based on this research, a hardware core mimicking human retinal imaging was proposed to enable advances in neuromorphic electronics, particularly in optical information sensing and learning.
APPLIED PHYSICS LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Mengyang Yuan, John Niroula, Qingyun Xie, Nitul S. Rajput, Kai Fu, Shisong Luo, Sagar Kumar Das, Abdullah Jubair Bin Iqbal, Bejoy Sikder, Mohamed Fadil Isamotu, Minsik Oh, Savannah R. Eisner, Debbie G. Senesky, Gary W. Hunter, Nadim Chowdhury, Yuji Zhao, Tomas Palacios
Summary: This letter presents an enhancement-mode GaN transistor technology that can operate in a simulated Venus environment for 10 days. The robustness of the transistor was evaluated through in-situ electrical characterization and advanced microscopy investigation. This is the first demonstration and comprehensive analysis of E-mode GaN transistors in such harsh environments, establishing it as a strong contender for harsh environment mixed-signal electronics.
IEEE ELECTRON DEVICE LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Alessandro Caria, Carlo De Santi, Matteo Buffolo, Marco Nicoletto, Xuanqi Huang, Houqiang Fu, Hong Chen, Yuji Zhao, Gaudenzio Meneghesso, Enrico Zanoni, Matteo Meneghini
Summary: The aim of this article is to investigate the degradation mechanisms of GaN solar cells under harsh conditions, specifically forward current stress. The results indicate that the main parameters of the cells decrease under this stress, and there is a correlation between the charge distribution inside the active region and the concentration of trap states. The decrease in power conversion efficiency is attributed to a redistribution of charge in the active region, resulting in an increase in midgap states density. These findings fill the gap in the literature regarding the long-term reliability of GaN solar cells under harsh conditions.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Energy & Fuels
Marco Nicoletto, Alessandro Caria, Fabiana Rampazzo, Carlo De Santi, Matteo Buffolo, Giovanna Mura, Francesca Rossi, Xuanqui Huang, Houqiang Fu, Hong Chen, Yuji Zhao, Gaudenzio Meneghesso, Enrico Zanoni, Matteo Meneghini
Summary: This study investigates the influence of V-pits on the electrical performance of high periodicity InGaN-GaN multiple quantum wells solar cells. Through combined electrical analysis, microscopy investigation, and simulations, it is found that V-pits can affect the turn-on voltage and current-voltage characteristics of the solar cells. The presence of V-pits allows for a closer connection between the quantum well region and the p-side contact. These findings provide insight into the role of V-pits in the electrical performance of high-periodicity quantum well devices.
IEEE JOURNAL OF PHOTOVOLTAICS
(2023)
Article
Nanoscience & Nanotechnology
Frank Angeles, Samreen Khan, Victor H. H. Ortiz, Mingfei Xu, Shisong Luo, Dinusha Herath Mudiyanselage, Houqiang Fu, Yuji Zhao, Richard B. B. Wilson
Summary: The thermal conductivity of wide bandgap semiconductor thin films has a significant impact on the performance of various devices. However, accurately measuring the thermal conductivity of sub-micrometer thin films with high values is difficult. This study proposes a combination of magneto-optic thermometry and TiN interfacial layers to enhance the spatiotemporal resolution of pump/probe thermal transport measurements.
Article
Nanoscience & Nanotechnology
Xiangkai Liu, Zhongzheng Wang, Hao Huang, Congye Liu, Wencheng Niu, Zhengdao Xie, Dandan Hao, Houqiang Fu, Xingqiang Liu, Xuming Zou, Fukai Shan, Zhenyu Yang
Summary: The integration of data storage and computing capabilities has led to the development of a microneuronal network system with high precision and speed rates. This article introduces an optoelectronic storage device based on a transistor, which enables the construction of logic gates and the simulation of future machine vision applications. The microneural network system achieves a recognition rate of 96.3% in a multidimensional color space.
ACS APPLIED NANO MATERIALS
(2023)
