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Chinese Physics Letters 2015年第2期32卷 60-62页

作者：刘颖慧张锦川江建民孙素娟李沛旭刘峰奇 Key Laboratory of semiconductor Materials Science Institute of SemiconductorsChinese Academy of Sciences Huaguang Optoelectronics Co.ltd.

We report on the room-temperature cascade laser （QCL） at λ -4.7μm. cw operation of a surface grating Both grating design and material distributed feedback （DFB） quantum optimization are used to decrease the threshold current density and to increase the output power. For a high-reflectivity-coated 13-μm-wide and 4- mm-long laser, high wall-plug efficiency of 6% is obtained at 20℃ from a single facet producing over I W of ew output power. The threshold current density of DFB QCL is as low as 1.13kA/cm^2 at 10℃ and 1.34kA/cm2 at 30℃ in cw mode. Stable single-mode emission with a side-mode suppression ratio of about 30 dB is observed in tile working temperature range of 20-50℃.

关键词： DFB QCL Development of Surface Grating Distributed Feedback Quantum Cascade Laser for High Output Power and Low Threshold Current Density

Performance improvement of c-Si solar cell by a combination of SiNx/SiOx passivation and double P-diffusion gettering treatment

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Journal of semiconductors 2017年第11期38卷 60-65页

作者： Xiaoyu Chen Youwen Zhao Zhiyuan Dong Guiying Shen Yongbiao Bai Jingming Liu Hui Xie Jiangbian He Key Laboratory of semiconductor Materials Science Beijing Key Laboratory of Low Dimensional Semiconductor Materials and Devices Institute of Semiconductors Chinese Academy of Sciences Beijing 100083 China College of Materials Science and Opto-Electronic Technology Univeristy of Chinese Academy of Sciences Beijing 100049 China solar Energy Technology Co. Ltd. Hohhot 010010 China

SiNx/SiOx passivation and double side P-diffusion gettering treatment have been used for the fabrication of c-Si solar cells. The solar cells fabricated have high open circuit voltage and short circuit current after the double P-diffusion treatment. In addition to better surface passivation effect, SiNx/SiOx layer has lower reflectivity in long wavelength range than conventional SiNx film. As a consequence, such solar cells exhibit higher conversion efficiency and better internal quantum efficiency, compared with conventional c-Si solar cells.

关键词： c-Si solar cell double diffusion SiNx/SiOx passivation

Characteristics and mechanisms of subthreshold voltage hysteresis in 4H-SiC MOSFETs

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Chinese Physics B 2021年第4期30卷 610-615页

作者： Xi-Ming Chen Bang-Bing Shi Xuan Li Huai-Yun Fan Chen-Zhan Li Xiao-Chuan Deng Hai-Hui Luo Yu-Dong Wu Bo Zhang School of Electronic Science and Engineering University of Electronic Science and Technology of ChinaChengdu 610054China State Key Laboratory of Advanced Power semiconductor Devices Zhuzhou CRRC Times Semiconductor Company Ltd.Zhuzhou 412001China

In order to investigate the characteristics and mechanisms of subthreshold voltage hysteresis(ΔV_(th,sub)) of 4 H-SiC metal-oxide-semiconductor field-effect transistors(MOSFETs),4 H-SiC planar and trench MOSFETs and corresponding P-type planar and trench metal-oxide-semiconductor(MOS) capacitors are fabricated and *** with planar MOSFEF,the trench MOSFET shows hardly larger ΔV_(th,sub) in wide temperature range from 25 0 C to 300 0 *** operating temperature range is from 25 ℃ to 300 ℃,the off-state negative V_(gs) of planar and trench MOSFETs should be safely above-4 V and-2 V,respectively,to alleviate the effect of ΔV_(th,sub) on the normal *** the help of P-type planar and trench MOS capacitors,it is confirmed that the obvious ΔV_(th,sub) of 4 H-SiC MOSFET originates from the high density of the hole interface traps between intrinsic Fermi energy level(E_(i)) and valence band(E_(v)).The maximumΔV_(th,sub) of trench MOSFET is about twelve times larger than that of planar MOSFET,owing to higher density of interface states(D_(it)) between E_(i) and E_(v).These research results will be very helpful for the application of 4 H-SiC MOSFET and the improvement of ΔV_(th,sub) of 4 H-SiC MOSFET,especially in 4 H-SiC trench MOSFET.

关键词： 4H-SiC MOSFET subthreshold voltage hysteresis P-type MOS capacitor density of interface states

Effects of gate-buffer combined with a p-type spacer structure on silicon carbide metal semiconductor field-effect transistors

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Chinese Physics B 2012年第1期21卷 426-432页

作者： Song Kun Chai Chang-Chun Yang Yin-Tang Chen Bin Zhang Xian-Jun Ma Zhen-Yang Key Laboratory of Wide Band-Gap semiconductor Materials and Devices of Ministry of Education School of MicroelectronicsXidian UniversityXi'an 710071China

An improved structure of silicon carbide metal-semiconductor field-effect transistors （MESFET） is proposed for high power microwave applications. Numerical models for the physical and electrical mechanisms of the device are presented, and the static and dynamic electrical performances are analysed. By comparison with the conventional structure, the proposed structure exhibits a superior frequency response while possessing better DC characteristics. A p-type spacer layer, inserted between the oxide and the channel, is shown to suppress the surface trap effect and improve the distribution of the electric field at the gate edge. Meanwhile, a lightly doped n-type buffer layer under the gate reduces depletion in the channel, resulting in an increase in the output current and a reduction in the gate-capacitance. The structural parameter dependences of the device performance are discussed, and an optimized design is obtained. The results show that the maximum saturation current density of 325 mA/mm is yielded, compared with 182 mA/mm for conventional MESFETs under the condition that the breakdown voltage of the proposed MESFET is larger than that of the conventional MESFET, leading to an increase of 79% in the output power density. In addition, improvements of 27% cut-off frequency and 28% maximum oscillation frequency are achieved compared with a conventional MESFET, respectively.

关键词： silicon carbide metal-semiconductor field-effect transistor p-type spacer gate-buffer

Characterization of Al_2O_3 /GaN/AlGaN/GaN metalinsulator-semiconductor high electron mobility transistors with different gate recess depths

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Chinese Physics B 2011年第2期20卷 458-464页

作者：马晓华潘才渊杨丽媛于惠游杨凌全思王昊张进成郝跃 School of Technical Physics Xidian University Key Laboratory for Wide Band-Gap semiconductor Materials and Devices School of MicroelectronicsXidian University

In this paper, in order to solve the interface-trap issue and enhance the transconductance induced by high-k dielectric in metal-insulator-semiconductor （MIS） high electron mobility transistors （HEMTs）, we demonstrate better performances of recessed-gate A1203 MIS-HEMTs which are fabricated by Fluorine-based Si3N4 etching and chlorine- based A1CaN etching with three etching times （15 s, 17 s and 19 s）. The gate leakage current of MIS-HEMT is about three orders of magnitude lower than that of A1GaN/CaN HEMT. Through the recessed-gate etching, the transconductanee increases effectively. When the recessed-gate depth is 1.02 nm, the best interface performance with Tit----（0.20--1.59） p^s and Dit ：（0.55-1.08）x 1012 ***- 1 can be obtained. After chlorine-based etching, the interface trap density reduces considerably without generating any new type of trap. The accumulated chlorine ions and the N vacancies in the AIGaN surface caused by the plasma etching can degrade the breakdown and the high frequency performances of devices. By comparing the characteristics of recessed-gate MIS-HEMTs with different etching times, it is found that a low power chlorine-based plasma etching for a short time （15 s in this paper） can enhance the performances of MIS-HEMTs effectively.

关键词： A1GaN/GaN gate-recessed MIS-HEMT frequency-dependent capacitance and conduc-tance drain current injection technique knee resistance

Quantitatively Exploring the Effect of a Triangular Electrode on Performance Enhancement in a 4H-SiC Metal-semiconductor-Metal Ultraviolet Photodetector

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Chinese Physics Letters 2011年第6期28卷 329-332页

作者： CHEN Bin YANG Yin-Tang CHAI Chang-Chun ZHANG Xian-Jun Key Laboratory of Ministry of Education for Wide Band-Gap semiconductor Materials and Devices School of MicroelectronicsXidian UniversityXi'an 710071

A model of novel triangular electrode metal-semiconductor-metal(TEMSM)and conventional electrode metal-semiconductor-metal(CEMSM)detectors is established by utilizing the ISE-TCAD *** comparing the simulated results of TEMSM and CEMSM with experimental data,the model validity is verified and the TEMSM detector shows a superiority of a 113%photocurrent increase of 25.4 nA and similar low dark current of 3.16 pA at 30 V bias over the CEMSM ***,the electrode angleα,width W and spacing S are optimized to obtain the enhanced device features including high UV−to-visible rejection ratio and large responsivity,*** 30 V bias,the maximum UV-to-visible rejection ratio,comparable responsivity and external quantum efficiency at 310 nm are 13049,0.1712 A/W and 68.48%for a TEMSM detector with device parameters ofα=60°,W=3μm and S=4μm,respectively.

关键词： electrode visible utilizing

Luminescence properties of red phosphors Ca_(10)Li(PO_4)_7:Eu^(3+)

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Journal of Rare Earths 2011年第5期29卷 440-443页

作者：宋恩海赵韦人周国雄豆喜华易春雨周民康 School of Physics & Optoelectronic Engineering Guangdong University of Technology Huizhou Unihero semiconductor Lighting Technology Co. Ltd.

A series of red phosphors Ca10Li （PO4）7：Eu3＋ were synthesized by high temperature solid-state reaction method. Their luminescence properties were characterized by means of photoluminescence excitation and emission spectra,CIE chromaticity and quantum efficiency. Results indicated that the phosphors could be effectively excited by the near ultraviolet （NUV） light （393 nm）. The main emission peaks of the phosphor were ascribed to the transition 5D0–7F2 （613 and 617 nm） of Eu3＋ ion when samples were excited by 393 nm. The CIE chromaticity （x,y） of Ca9.9Li （PO4）7：0.10Eu3＋ was x=0.638,y=0.361 and the quantum efficiency of this phosphor was 75% excited by 393 nm. Therefore,this phosphor could be a promising red component for the applications in white LEDs.

关键词： Ca10Li(PO4)7:Eu3+ LED red phosphor rare earths

Gradual variation method for thick GaN heteroepitaxy by hydride vapour phase epitaxy

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Chinese Physics B 2011年第9期20卷 439-444页

作者：杜彦浩吴洁君罗伟科 John Goldsmith 韩彤陶岳彬杨志坚于彤军张国义 Research Centre for Wide-gap semiconductors School of PhysicsPeking University Beijing Yanyuan Research Centre Sino Nitride Semiconductor LTD

Two strain-state samples of GaN, labelled the strain-relief sample and the quality-improved sample, were grown by hydride vapour phase epitaxy （HVPE）, and then characterized by high-resolution X-ray diffraction, photoluminescence and optical microscopy. Two strain states of GaN in HVPE, like 3D and 2[） growth modes in metal-organic chemical vapour deposition （MOCVD）, provide an effective way to solve the heteroepitaxial problems of both strain relief and quality improvement. The gradual variation metbod （GVM）, developed based on the two strain states, is characterized by growth parameters＇ gradual variation alternating between the strain-relief growth conditions and the quality-improved growth conditions. In GVM, the introduction of the strain-relief amplitude, which is defined by the range from the quality-improved growth conditions to the strain-relief growth conditions, makes the strain-relief control concise and effective. The 300-μm thick bright and crack-free GaN film grown on a two-inch sapphire proves the effectiveness of GVM.

关键词： GaN hydride vapour phase epitaxy heteroepitaxy

Growth of ZnO Single Crystal by Chemical Vapor Transport Method

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Journal of Rare Earths 2006年第Z1期24卷 4-7页

作者： Zhao Youwen Dong Zhiyuan Wei Xuecheng Duan Manlong Li Jinmin Institute of semiconductor Chinese Academy of Sciences Beijing 100083 China Institute of Semiconductor Chinese Academy of Sciences Beijing 100083 China Institute of Semiconductor Chinese Academy of Sciences Beijing 100083 China Institute of Semiconductor Chinese Academy of Sciences Beijing 100083 China Institute of Semiconductor Chinese Academy of Sciences Beijing 100083 China

ZnO crystals were grown by CVT method in closed quartz tube under seeded condition. Carbon was used as a transport agent to enhance the chemical transport of ZnO in the growth process. ZnO single crystals were grown by using GaN/sapphire and GaN/Si wafer as seeds. The property and crystal quality of the ZnO single crystals was studied by photoluminescence spectroscopy and X-ray diffraction technique.

关键词： zinc oxide chemical vapor transport single crystal growth

Growth of High Quality Semi-Insulating InP Single Crystal by Suppression of Compensation Defects

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Journal of Rare Earths 2006年第Z1期24卷 75-77页

作者： Zhao Youwen Dong Zhiyuan Duan Manlong Sun Wenrong Yang Zixiang Institute of semiconductor Chinese Academy of Sciences Beijing 100083 China Institute of Semiconductor Chinese Academy of Sciences Beijing 100083 China Institute of Semiconductor Chinese Academy of Sciences Beijing 100083 China Institute of Semiconductor Chinese Academy of Sciences Beijing 100083 China Institute of Semiconductor Chinese Academy of Sciences Beijing 100083 China

Deep level defects in as-grown and annealed SI-InP samples were investigated by thermally stimulated current spectroscopy. Correlations between electrical property, compensation ratio, thermal stability and deep defect concentration in SI-InP were revealed. An optimized crystal growth condition for high quality SI-InP was demonstrated based on the experimental results.

关键词： indium phosphide defect semi-insualting