Article
Engineering, Electrical & Electronic
Yucai Xie, Haotian Shi, Hongpeng Zhang, Shuang Yu, Lebile Llerioluwa, Yiwen Zheng, Guobin Li, Yuqing Sun, Haiquan Chen
Summary: A bridge-type inductance sensor with a two-stage filter circuit is proposed for high-precision detection of metal debris in oil. The sensor utilizes a Wheatstone bridge structure sensing unit and a circuit with rectification, amplitude modulation, and amplification functions to improve detection accuracy and extract weak abrasive signals submerged in noise. By adjusting the passband gain of the two-stage filter circuit, the measurement range of the sensor voltage value is improved, providing technical support for fault diagnosis and prevention in hydraulic systems.
IEEE SENSORS JOURNAL
(2021)
Article
Engineering, Electrical & Electronic
Yuanfei Zhang, Fenglei Ni, Hong Liu
Summary: A novel Wheatstone bridge adjustment circuit with both rough-tuning and fine-tuning functions is designed. The circuit consists of parametric circuit structure, rough-tuning sub-circuit with series-parallel-resistor (SPR) structures, and fine-tuning sub-circuit with a resistor and a digital-to-analog converter (DAC). The circuit effectively eliminates bridge imbalance in the manufacturing stage and compensates for additional imbalance in the application stage caused by external factors. The effectiveness of the circuit is verified on a six-axis force/torque sensor developed for the Chinese Space Station.
IEEE SENSORS JOURNAL
(2023)
Article
Chemistry, Physical
Jiyu Zhou, Xiaobo Li, Taofei Pu, Yue He, Xiao Wang, Yuyu Bu, Liuan Li, Jin-Ping Ao
Summary: AlGaN/GaN ion-sensitive field-effect transistors (ISFETs) with stacked and high Al-content AlGaN barrier were fabricated as pH sensors, showing good sensitivity but degraded electrical performance after exposure to alkaline solution, due to surface etching and transformation of AlGaN into surface oxide.
APPLIED SURFACE SCIENCE
(2021)
Article
Materials Science, Multidisciplinary
Kavita T. Upadhyay, Manju K. Chattopadhyay
Summary: This paper provides a review of significant research work in the field of GaN-based sensor technologies, including classification of existing work, explanation of sensor sensing mechanisms, as well as the challenges and future opportunities facing current sensing systems.
MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS
(2021)
Article
Engineering, Multidisciplinary
Hyun-Seok Cha, Seong-Hyun Hwang, Dae-Hwan Kim, Hyuck-In Kwon, Sang-Hun Song
Summary: An offset cancelling circuit based on a Wheatstone bridge for a Hall effect sensor was designed and investigated, not only eliminating offset voltage caused by misalignment but also providing voltage gain. The circuit, using a JFET and resistors, operated as a common source amplifier with a gain of 26.4, linearly amplifying the offset cancelled Hall voltage with a magnetic field.
Article
Optics
Anthonin Delphan, Maxim N. Makhonin, Tommi Isoniemi, Paul M. Walker, Maurice S. Skolnick, Dmitry N. Krizhanovskii, Dmitry V. Skryabin, Jean-Francois Carlin, Nicolas Grandjean, Raphael Butte
Summary: We observed polariton lasing in micro-ring resonators based on GaN/AlGaN slab waveguides in the UV spectral range, with stimulated polariton relaxation into multiple ring resonator modes. The strong exciton-photon coupling regime was confirmed by the reduction of the free spectral range and the blueshift of the exciton-like modes with increasing pulse energy. The absence of broadening in the exciton emission further confirmed lasing at low electron-hole densities. Overall, our work paves the way for the development of novel UV devices based on high-speed slab waveguide polariton geometry operating up to room temperature and integrated into complex photonic circuits.
Article
Chemistry, Analytical
Robert Sokolovskij, Hongze Zheng, Wenmao Li, Guangnan Zhou, Qing Wang, Guoqi Zhang, Hongyu Yu
Summary: The particulate matter micro-sensor for automotive exhaust systems based on a gateless wide-bandgap AlGaN/GaN high electron mobility transistor was developed and tested. The sensor showed good sensitivity towards soot and fast response time, with successful regeneration post-soot deposition indicating high temperature stability and harsh environment operation compatibility. However, further optimization is needed to mitigate high-temperature interdiffusion.
SENSORS AND ACTUATORS B-CHEMICAL
(2021)
Article
Chemistry, Analytical
Wei-Cheng Chen, Jing-Shiuan Niu, I-Ping Liu, Bu-Yuan Ke, Shiou-Ying Cheng, Wen-Chau Liu
Summary: A new hydrogen sensor incorporating Pt nanoparticles and film shows high sensitivity and wide detection ranges for hydrogen concentration and operating temperature. Experimental results demonstrate excellent sensing performance with high sensitivity and fast response times.
SENSORS AND ACTUATORS B-CHEMICAL
(2021)
Article
Physics, Applied
Lingxi Xia, Kailin Ren, Chih-Fang Huang, Yung C. Liang
Summary: This study presents a high sensitivity magnetic field sensor achieved through AlGaN/GaN fin-shaped structure, with laboratory measurements showing even higher sensitivity at narrower fin widths. The sensor exhibits low power consumption and is able to detect minimum magnetic flux at 20 mu Tau.
APPLIED PHYSICS LETTERS
(2021)
Article
Engineering, Electrical & Electronic
Jianwen Sun, Teng Zhan, Robert Sokolovskij, Zewen Liu, Pasqualina M. Sarro, Guoqi Zhang
Summary: A suspended gate-recessed Pt/AlGaN/GaN heterostructure gas sensor with an integrated micro-heater was fabricated and characterized using a precision two-step gate recess technique. The sensitivity and current change to NO2/air were significantly improved compared to conventional devices, and the response time was reduced to only about 25% of the value for conventional devices. The sensor also demonstrated excellent repeatability and cross-sensitivity.
IEEE SENSORS JOURNAL
(2021)
Article
Engineering, Electrical & Electronic
Xiaoshuai An, Yumeng Luo, Binlu Yu, Liang Chen, Kwai Hei Li
Summary: The research demonstrates a novel integration of GaN chip with microdome-patterned PDMS film for pressure sensing, showing high sensitivity and stability for a wide range of applications.
IEEE ELECTRON DEVICE LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Dong Xie, Chunling Xu, Xiwei Yao, An Min Wang
Summary: The quantum version of a special classical Wheatstone bridge has been proposed, which is built with a boundary-driven spin system. We introduce a quantum Wheatstone bridge consisting of Bose systems, capable of simulating the general classical Wheatstone bridge. Balancing the quantum Wheatstone bridge can result in obtaining an unknown coupling, determined through homodyne detection. The precision of measurement is optimal when the quantum Wheatstone bridge is balanced, as shown by calculating the quantum Fisher information. Additionally, homodyne detection is an effective measurement method in low-temperature environments.
RESULTS IN PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
June-Heang Choi, Taehyun Park, Jaehyun Hur, Ho-Young Cha
Summary: An AlGaN/GaN heterostructure based hydrogen sensor was fabricated with a dual catalyst layer of ZnO-nanoparticles atop a Pd catalyst film. The sensor operated at room temperature without heating, thanks to the photocatalytic reaction of ZnO-NPs with ultraviolet illumination. It showed a sensing response of 25% for a hydrogen concentration of 4% at room temperature, with fast response and recovery times of 8 s and 11 s, respectively.
Article
Engineering, Electrical & Electronic
Ting Li, Haiping Shang, Qunying Zhang, Weibing Wang
Summary: By changing the longitudinal resistance and transverse resistance, the nonlinearity of pressure sensors can be effectively reduced, and a method for optimizing the nonlinearity of piezoresistive pressure sensors was proposed, which could reduce nonlinearity by several orders of magnitude in simulation.
MICROSYSTEM TECHNOLOGIES-MICRO-AND NANOSYSTEMS-INFORMATION STORAGE AND PROCESSING SYSTEMS
(2021)
Article
Engineering, Electrical & Electronic
Chia-Hao Liu, Hsien-Chin Chiu, Hsiang-Chun Wang, Hsuan-Ling Kao, Chong-Rong Huang
Summary: The study shows that DJ-HEMT exhibits higher gate voltage swing in the gate region due to the dual junction, enhancing gate performance. Compared to ST-HEMT, DJ-HEMT has higher V-TH, saturation current, I-ON/I-OFF ratio, and gate swing voltage. In addition, DJ-HEMT also has lower leakage current and longer lifetime measurement.
IEEE ELECTRON DEVICE LETTERS
(2021)
Article
Physics, Applied
Yuxia Feng, Huarui Sun, Xuelin Yang, Kang Liu, Jie Zhang, Jianfei Shen, Danshuo Liu, Zidong Cai, Fujun Xu, Ning Tang, Tongjun Yu, Xinqiang Wang, Weikun Ge, Bo Shen
Summary: High-quality GaN films on SiC with low thermal boundary resistance are achieved by using an ultrathin low Al content AlGaN buffer layer, which improves crystal quality and reduces thermal boundary resistance simultaneously. Enhanced lateral growth rate contributes to the formation of basal plane stacking faults in GaN, significantly reducing threading dislocation density. The mechanisms of reducing thermal boundary resistance and dislocation density by the ultrathin buffer layer are revealed, showing importance for performance improvement and cost reduction of higher power GaN-on-SiC electronics.
APPLIED PHYSICS LETTERS
(2021)
Article
Physics, Applied
Cheng Ma, Xuelin Yang, Jianfei Shen, Danshuo Liu, Zidong Cai, Zhenghao Chen, Jun Tang, Liwen Sang, Fujun Xu, Xinqiang Wang, Weikun Ge, Bo Shen
Summary: Aluminum diffusion is one of the main contributors to RF loss in GaN-on-Si RF devices. The flow rate of trimethylaluminum (TMAl) is found to be a significant factor in the diffusion process. By restricting the preflow rate of TMAl, high-quality GaN layers with low RF loss and dislocation density have been achieved on Si substrates.
APPLIED PHYSICS EXPRESS
(2022)
Article
Physics, Applied
Xiaoguang He, Yuxia Feng, Xuelin Yang, Shan Wu, Zidong Cai, Jia Wei, Jianfei Shen, Huayang Huang, Danshuo Liu, Zhenghao Chen, Cheng Ma, Weikun Ge, Bo Shen
Summary: This work investigates the impact of strain relief layers (SRL) on the degradation of dynamic on-resistance (R(on)) in GaN power devices on Si. The study reveals that the SRL plays an important role in the dynamic R(on) degradation. Enhancing the carrier blocking ability of the SRL can effectively suppress the degradation of dynamic R(on).
APPLIED PHYSICS EXPRESS
(2022)
Article
Physics, Applied
Huanying Sun, Liwen Sang, Xiulin Shen, Xuelin Yang, Tiefu Li, J. Q. You, Bo Shen, Meiyong Liao
Summary: This study demonstrates that highly stressed GaN on Si nanomechanical resonators exhibit high quality factor and low temperature coefficient of resonance frequency at elevated temperatures. This is achieved through the high stress and geometrical nonlinearity of dynamical strain in the GaN resonator, which compensates for the dissipation caused by the change of material properties with increasing temperature.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Nanoscience & Nanotechnology
Wenjie Song, Jie Zhang, Zheyang Zheng, Sirui Feng, Xuelin Yang, Bo Shen, Kevin J. Chen
Summary: This study reports GaN high-electron-mobility transistors (HEMTs) with a thick GaN buffer on a low-resistivity silicon (LRS) substrate. The HEMTs exhibit high performance in both radio-frequency amplification and power conversion, thanks to the low dislocation density and high vertical voltage blocking capability of the thick GaN buffer.
Article
Physics, Applied
Danshuo Liu, Xuelin Yang, Xing Zhang, Zidong Cai, Zhenghao Chen, Cheng Ma, Hongcai Yang, Fujun Xu, Xinqiang Wang, Weikun Ge, Bo Shen
Summary: Buffer-free GaN layers with a thickness of 1.5 μm can be directly grown on PVD-AlN/Si templates using delayed coalescence growth. The low density and large size AlN nuclei in PVD-AlN, together with the 3D growth mode of GaN, contribute to crack-free growth.
APPLIED PHYSICS EXPRESS
(2022)
Article
Physics, Applied
Shan Wu, Xuelin Yang, Zhenxing Wang, Zhongwen Ouyang, Huayang Huang, Qing Zhang, Qiuyu Shang, Zhaohua Shen, Fujun Xu, Xinqiang Wang, Weikun Ge, Bo Shen
Summary: This study demonstrates that C doping methods have a significant influence on the charge state of C N and the interaction between H and C in GaN. Different doping methods lead to changes in the charge state of C N and the formation of C-H complexes.
APPLIED PHYSICS LETTERS
(2022)
Article
Physics, Applied
Shan Wu, Xuelin Yang, Huayang Huang, Zhaohua Shen, Yuanyuan Xue, Han Yang, Liubing Wang, Fujun Xu, Xinqiang Wang, Weikun Ge, Bo Shen
Summary: This study clarifies the shift of Fermi level and conductivity type in heavily C-doped GaN, and attributes the reverse transition to self-compensation and other donor-type compensation centers introduced along with C doping.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2022)
Article
Physics, Applied
Xuelin Yang, Jianfei Shen, Zidong Cai, Zhenghao Chen, Bo Shen
Summary: This study investigates the influence of C doping on dislocation behaviors in GaN. It is found that moderate C doping can reduce dislocation density, but further increasing C concentration leads to an increase in dislocation density. Additionally, C doping has a greater impact on edge dislocations than screw dislocations. The stress evolution in the GaN layer is consistent with the observed dislocation behaviors, suggesting a mechanism where C impurities are incorporated into different lattice locations in GaN with increasing doping levels.
APPLIED PHYSICS EXPRESS
(2022)
Article
Physics, Applied
Huayang Huang, Xiaolan Yan, Xuelin Yang, Wensheng Yan, Zeming Qi, Shan Wu, Zhaohua Shen, Ning Tang, Fujun Xu, Xinqiang Wang, Weikun Ge, Bing Huang, Bo Shen
Summary: By combining experimental observations and first-principles simulations, it was found that in p-type GaN, the C impurity mainly occupies the N site rather than the Ga site, and this phenomenon is attributed to an H-induced E-F tuning effect. This work not only provides clear evidence for C defect formation in p-GaN, but also significantly contributes to understanding the role of C-related hole-killers in the electrical and optoelectrical properties of p-GaN and even p-AlGaN.
APPLIED PHYSICS LETTERS
(2022)
Article
Physics, Applied
Huayang Huang, Xuelin Yang, Zhaohua Shen, Zhenghao Chen, Ning Tang, Fujun Xu, Xinqiang Wang, Weikun Ge, Bo Shen
Summary: An equilibrium carrier statistics approach with a partial ionization model is proposed to determine the energy level of CN deep donors in p-type GaN with heavy Mg doping. The energy level of the CN donor is determined to be EV + (0.20 +/- 0.01) eV at elevated temperatures using the partial ionization model. The ionization ratio of CN is found to be dependent on the C concentration and can be estimated to be in the range of 0.3-0.8. Such partial ionization characteristic of CN may affect device reliability by capturing/emitting free carriers.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Chemistry, Physical
Jiaming Wang, Nan Xie, Fujun Xu, Lisheng Zhang, Jing Lang, Xiangning Kang, Zhixin Qin, Xuelin Yang, Ning Tang, Xinqiang Wang, Weikun Ge, Bo Shen
Summary: We propose a method to achieve high-quality III-nitride heteroepitaxial films by controlling the discretization and coalescence of columns. By using nano-patterned AlN/sapphire templates, discrete AlN columns coalesce with uniform orientations, effectively suppressing the regeneration of threading dislocations. The resulting AlN heteroepitaxial film shows a density of dislocation etch pits close to that of bulk single crystals.
Article
Nanoscience & Nanotechnology
Jie Zhang, Xuelin Yang, Hongping Ma, Qingchun Zhang, Bo Shen
Summary: We present the impact of Al dopants and threading dislocations on dislocation inclinations and their role in controlling residual strain in GaN-on-Si epitaxial films. Increasing the Al concentration in the GaN film to 0.85% results in dislocations extending predominantly in the growth direction, leading to a strain-free epitaxial film. Our findings suggest that Al atoms can substitute for Ga vacancies at dislocation cores and inhibit dislocation inclinations, thereby reducing compressive strain relaxation. These results offer a novel approach to control dislocation movements and strain in GaN epitaxial films on Si substrates.
Article
Engineering, Electrical & Electronic
Zidong Cai, Xuelin Yang, Cheng Ma, Zhenghao Chen, Danshuo Liu, Liwen Sang, Fujun Xu, Xinqiang Wang, Weikun Ge, Bo Shen
Summary: An ultralow-supersaturation Al pretreatment approach has been proposed to achieve low threading dislocation density and low RF loss GaN/AlN layer stacks on Si substrates. The approach eliminates the Al-Si liquid alloy and results in a sharp AlN/Si interface. It also enlarges the size of AlN nucleation islands, reducing the generated threading dislocations. As a result, a crack-free GaN layer can be obtained directly on the low dislocation density AlN layer without the need for transition layers.
ACS APPLIED ELECTRONIC MATERIALS
(2022)
Article
Engineering, Electrical & Electronic
Liuyun Yang, Jinlin Wang, Shanshan Sheng, Baoqing Zhang, Bowen Sheng, Tao Wang, Fang Liu, Renchun Tao, Fujun Xu, Xuelin Yang, Weikun Ge, Bo Shen, Xinqiang Wang
Summary: In this article, a low-resistive Ohmic contact in AlN/GaN heterostructures with high electron mobility was achieved by rapid thermal annealing. The incorporation of oxygen was identified as the main obstacle for Ohmic contacts, which formed Al2O3 and voids in the interlayers. By suppressing the incorporation of oxygen, a complete polycrystalline alloy without oxides was achieved, resulting in a low contact resistance of approximately 0.33 Ω·mm. The restrictions for Ohmic contacts in high-mobility AlN/GaN heterostructures were also clarified.
ACS APPLIED ELECTRONIC MATERIALS
(2022)