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Damage evolution and removal behaviors of GaN crystals involved in double-grits grinding

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International Journal of Extreme Manufacturing 2024年第2期6卷 469-484页

作者： Chen Li Yuxiu Hu Zongze Wei Chongjun Wu Yunfeng Peng Feihu Zhang Yanquan Geng State Key Laboratory of Robotics and System(HIT) Harbin Institute of TechnologyHarbin 150001People’s Republic of China Key Laboratory of Microsystems and Microstructures Manufacturing(HIT) Harbin Institute of TechnologyHarbin 150001People’s Republic of China College of Mechanical Engineering Donghua UniversityShanghai 201620People’s Republic of China Department of Mechanical and Electrical Engineering Xiamen UniversityXiamen 361005People’s Republic of China

Elucidating the complex interactions between the work material and abrasives during grinding of gallium nitride(GaN)single crystals is an active and challenging research area.In this study,molecular dynamics simulations were performed on double-grits interacted grinding of GaN crystals;and the grinding force,coefficient of friction,stress distribution,plastic damage behaviors,and abrasive damage were systematically investigated.The results demonstrated that the interacted distance in both radial and transverse directions achieved better grinding quality than that in only one direction.The grinding force,grinding induced stress,subsurface damage depth,and abrasive wear increase as the transverse interacted distance increases.However,there was no clear correlation between the interaction distance and the number of atoms in the phase transition and dislocation length.Appropriate interacted distances between abrasives can decrease grinding force,coefficient of friction,grinding induced stress,subsurface damage depth,and abrasive wear during the grinding process.The results of grinding tests combined with cross-sectional transmission electron micrographs validated the simulated damage results,i.***.amorphous atoms,high-pressure phase transition,dislocations,stacking faults,and lattice distortions.The results of this study will deepen our understanding of damage accumulation and material removal resulting from coupling between abrasives during grinding and can be used to develop a feasible approach to the wheel design of ordered abrasives.

关键词： grinding double-grits molecular dynamics damage material removal gallium nitride

High laser damage threshold reflective optically addressed liquid crystal light valve based on gallium nitride conductive electrodes

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High Power Laser Science and Engineering 2022年第6期10卷 8-14页

作者： Zhibo Xing Wei Fan Dajie Huang He Cheng Tongyao Du National Laboratory on High Power Laser and Physics Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghaiChina Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijingChina

In this paper,the feasibility of a high laser damage threshold liquid crystal spatial light modulator based on gallium nitride(GaN)transparent conductive electrodes is proved.The laser-induced damage threshold(LIDT)is measured,and a high LIDT reflective optically addressed liquid crystal light valve(OALCLV)based on GaN is designed and fabricated.The proper work mode of the OALCLV is determined;the OALCLV obtained a maximum reflectivity of about 55%and an on–off ratio of 55:1,and an image response is demonstrated.

关键词： gallium nitride laser-induced damage threshold liquid crystal optically addressed liquid crystal light valve

Self-screening of the polarized electric field in wurtzite gallium nitride along[0001]direction

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Chinese Physics B 2022年第4期31卷 589-596页

作者：丘秋凌杨世旭吴千树黎城朗张琦张津玮刘振兴张源涛刘扬 School of Electronics and Information Technology Sun Yat-Sen UniversityGuangzhou 510275China States Key Laboratory of Integrated Optoelectronics College of Electronic Science and EngineeringJilin UniversityChangchun 130012China

The strong polarization effect of GaN-based materials is widely used in high-performance devices such as white-lightemitting diodes(white LEDs),high electron mobility transistors(HEMTs),and GaN polarization superjunctions.However,the current researches on the polarization mechanism of GaN-based materials are not sufficient.In this paper,we studied the influence of polarization on electric field and energy band characteristics of Ga-face GaN bulk materials by using a combination of theoretical analysis and semiconductor technology computer-aided design(TCAD) simulation.The selfscreening effect in Ga-face bulk GaN under ideal and non-ideal conditions is studied respectively.We believe that the formation of high-density two-dimensional electron gas(2 DEG) in GaN is the accumulation of screening charges.We also clarify the source and accumulation of the screening charges caused by the GaN self-screening effect in this paper and aim to guide the design and optimization of high-performance GaN-based devices.

关键词： gallium nitride polarized electric field self-screening effect surface states donor doping intrinsic thermal excitation

Growth of gallium nitride Films on Multilayer Graphene Template Using Plasma-Enhanced Atomic Layer Deposition

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Acta Metallurgica Sinica(English Letters) 2019年第12期32卷 1530-1536页

作者： Ying-Feng He Mei-Ling Li San-Jie Liu Hui-Yun Wei Huan-Yu Ye Yi-Meng Song Peng Qiu Yun-Lai An Ming-Zeng Peng Xin-He Zheng School of Mathematics and Physics Beijing Key Laboratory for Magneto-Photoelectrical Composite and Interface ScienceUniversity of Science and Technology Beijing

In this work,the GaN thin films were directly deposited on multilayer graphene(MLG)by plasma-enhanced atomic layer deposition.The deposition was carried out at a low temperature using triethylgallium(TEGa)precursor and Ar/N2/H2 plasma.Chemical properties of the bulk GaN and GaN-graphene interface were analyzed using X-ray photoelectron spectroscopy.The sharp interface between GaN and graphene was verified via X-ray reflectivity and transmission electron microscope.The microstructures and the nucleation behaviors of the GaN grown on graphene have been also studied.The results of grazing incidence X-ray diffraction and Raman spectrum indicate that the as-deposited sample is polycrystalline with wurtzite structure and has a weakly tensile stress.Optical properties of the sample were investigated by photoluminescence(PL)at room temperature.The successful growth of GaN on MLG at a low temperature opens up the possibility of ameliorating the performance of electronic and optical devices based on GaN/graphene heterojunction.

关键词： Plasma-enhanced atomic layer deposition gallium nitride Graphene Interface microstructure

Direct growth of graphene on gallium nitride by using chemical vapor deposition without extra catalyst

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Chinese Physics B 2014年第9期23卷 358-363页

作者：赵云王钢杨怀超安铁雷陈闽江余芳陶立羊建坤魏同波段瑞飞孙连峰 Semiconductor Lighting Technology Research and Development Center Institute of SemiconductorsChinese Academy of Sciences National Center for Nanoscience and Technology University of Chinese Academy of Sciences

Graphene on gallium nitride （GaN） will be quite useful when the graphene is used as transparent electrodes to improve the performance of gallium nitride devices. In this work, we report the direct synthesis of graphene on GaN without an extra catalyst by chemical vapor deposition. Raman spectra indicate that the graphene films are uniform and about 5-6 layers in thickness. Meanwhile, the effects of growth temperatures on the growth of graphene films are systematically studied, of which 950 ℃ is found to be the optimum growth temperature. The sheet resistance of the grown graphene is 41.1 Ω/square, which is close to the lowest sheet resistance of transferred graphene reported. The mechanism of graphene growth on GaN is proposed and discussed in detail. XRD spectra and photoluminescence spectra indicate that the quality of GaN epi-layers will not be affected after the growth of graphene.

关键词： graphene photoluminescence gallium nitride chemical vapor deposition Raman spectroscopy

In-situ multi-information measurement system for preparing gallium nitride photocathode

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Chinese Physics B 2012年第3期21卷 1-4页

作者：付小倩常本康钱芸生张俊举 Institute of Electronic Engineering and Optoelectronic Technology Nanjing University of Science and Technology School of Information Science and Engineering University of Jinan

We introduce the first domestic in-situ multi-information measurement system for a gallium nitride （GaN） photo- cathode. This system can successfully fulfill heat cleaning and activation for GaN in an ultrahigh vacuum environment and produce a GaN photocathode with a negative electron affinity （NEA） status. Information including the heat clean- ing temperature, vacuum degree, photocurrent, electric current of cesium source, oxygen source, and the most important information about the spectral response, or equivalently, the quantum efficiency （QE） can be obtained during prepa- ration. The preparation of a GaN photocathode with this system indicates that the optimal heating temperature in a vacuum is about 700 ~C. We also develop a method of quickly evaluating the atomically clean surface with the vacuum degree versus wavelength curve to prevent possible secondary contamination when the atomic level cleaning surface is tested with X-ray photoelectron spectroscopy. The photocurrent shows a quick enhancement when the current ratio between the cesium source and oxygen source is 1.025. The spectral response of the GaN photocathode is flat in a wavelength range from 240 nm to 365 nm, and an abrupt decline is observed at 365 nm, which demonstrates that with the in-si$u multi-information measurement system the NEA GaN photocathode can be successfully prepared.

关键词： gallium nitride photocathode in-situ multi-information measurement

Optimization of gallium nitride-based laser diode through transverse modes analysis

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Chinese Optics Letters 2007年第10期5卷 588-590页

作者： Xiaomin Jin 章蓓 Liang Chen 代涛张国义 Electrical Engineering Department California Polytechnic State University San Luis Obispo CA 93407 USA School of Physics and State Key Laboratory for Artificial Microstructures and Mesoscopic Physics Peking University Beijing 100871 RSoft Design Group Inc. 400 Executive Boulevard Suite 100 Ossining NY 10562 USA

We investigate the transverse mode pattern in GaN quantum-well （QW） laser diode （LD） by numerical calculation. We optimize the current GaN LD structure by varying the n-GaN layer thickness. The n-type GaN layer is an important factor to determine the optical mode. Finally, we discuss the lasing performance of the GaN LD based on the transverse optical modes.

关键词： gallium nitride Laser modes Optimization Semiconductor quantum wells

Direct growth of graphene on gallium nitride using C2H2 as carbon source

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Frontiers of physics 2016年第2期11卷 97-102页

作者：王兵赵云伊晓燕王国宏刘志强段瑞飞黄鹏王军喜李晋闽 Semiconductor Lighting Technology R&D Center Institute of Semiconductors Chinese Academy of Sciences Beijing 100083 China

Growing graphene on gallium nitride （GaN） at temperatures greater than 900℃ is a challenge that must be overcome to obtain high quality of GaN epi-layers. We successfully met this challenge using C2H2 as the carbon source. We demonstrated that graphene can be grown both on copper and directly on GaN epi-layers. The Raman spectra indicated that the graphene films were about 4-5 layers thick. Meanwhile, the effects of the growth temperature on the growth of the graphene films were systematically studied, and 830℃ was found to be the optimum growth temperature. We successfully grew high-quality graphene films directly on gallium nitride.

关键词： graphene C2H2 gallium nitride chemical vapor deposition Raman spectroscopy

Plasma atomic layer etching of GaN/AlGaN materials and application: An overview

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Journal of Semiconductors 2022年第11期43卷 70-77页

作者： Lulu Guan Xingyu Li Dongchen Che Kaidong Xu Shiwei Zhuang School of Physics and Electronic Engineering Jiangsu Normal UniversityXuzhou 221116China Jiangsu Leuven Instruments Co.Ltd Xuzhou 221300China

With the development of the third generation of semiconductor devices,it is essential to achieve precise etching of gallium nitride(GaN)materials that is close to the atomic level.Compared with the traditional wet etching and continuous plasma etching,plasma atomic layer etching(ALE)of GaN has the advantages of self-limiting etching,high selectivity to other materials,and smooth etched surface.In this paper the basic properties and applications of GaN are presented.It also presents the various etching methods of GaN.GaN plasma ALE systems are reviewed,and their similarities and differences are compared.In addition,the industrial application of GaN plasma ALE is outlined.

关键词： gallium nitride plasma etching atomic layer etching self-limiting