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Preparation, characterization and nonlinear optical properties of colloidal gallium arsenide nanocrystals

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Rare Metals 2006年第2期25卷 118-123页

作者： LIU Zhengang LIU Chunling LI Quanshui CHEN Zhijian GONG Qihuang Department of Physics ＆ State Key Laboratory for Mesoscopic Physics Peking University Beijing 100871 China

GaAs nanocrystals were prepared via a simple mechanical ball milling technique. The prepared GaAs nanocrystals have high purity and could form colloidal ethanol suspension without any surfactant additives. The colloidal GaAs nanocrystal suspension displayed excellent two-photon absorption property over the visible and near-infrared region from 490 nm to 1064 nm, which enables it to become a promising broadband optical limiting material.

关键词： gallium arsenide nanocrystals nonlinear optics ball milling technique

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Burst mode enabled ultrafast laser inscription inside gallium arsenide

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International Journal of Extreme Manufacturing 2022年第4期4卷 179-187页

作者： Andong Wang Pol Sopeña David Grojo Aix-Marseille University CNRSLP3UMR734113009 MarseilleFrance

Ultrafast laser inscription(ULI)inside semiconductors offers new perspectives for 3D monolithic structures to be fabricated and new functionalities to be added in electronic and photonic ***,important challenges remain because of nonlinear effects such as strong plasma generation that distort the energy delivery at the focal point when exposing these materials to intense infrared *** to now,the successful technological demonstrations have primarily concentrated on silicon(Si).In this paper,we target at another important semiconductor:gallium arsenide(GaAs).With nonlinearities higher than those of Si,3D-machining of GaAs with femtosecond pulses becomes even ***,we show that the difficulty can be circumvented by burst-mode *** generate and apply trains of pulses at terahertz repetition rates for efficient pulse-to-pulse accumulation of laser-induced free carriers in the focal region,while avoiding an overdose of prefocal *** superior performance of burst-mode irradiation is confirmed by a comparative study conducted with infrared luminescence *** results indicate a successful reduction of the plasma density in the prefocal region so that higher pulse energy reaches the focal *** same method is applied to identify optimum irradiation conditions considering particular cases such as asymmetric pulse trains and aberrated *** 64-pulse trains,we successfully manage to cross the writing threshold providing a solution for ULI inside *** application potential is finally illustrated with a stealth dicing demonstration by taking benefit of the burst *** irradiation method opens wide possibilities for 3D structuring inside GaAs by ULI.

关键词： laser processing ultrafast laser inscription THz-repetition-rate burst semiconductors gallium arsenide

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Dark Current Compensation and Sensitivity Adjustment on gallium arsenide Linear Array Detector for X-Ray Imaging

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Journal of Biomedical Science and Engineering 2016年第11期9卷 532-543页

作者： Mikhail Polkovnikov Department of Experimental Physics Institute for High Energy Physics (IHEP) National Research Center “Kurchatov Institute” Protvino Russia

For the last several years, the linear array x-ray detector for x-ray imaging with gallium arsenide direct conversion sensitive elements has been developed and tested at the In-stitute for High Energy Physics. The array consists of 16 sensitive modules. Each module has 128 gallium arsenide (GaAs) sensitive elements with 200 μm pitch. Current article describes two key program procedures of initial dark current compensation of each sensitive element in the linear array, and sensitivity adjustment for alignment of strip pattern in the raw image data. As a part of evaluation process a modular transfer function (MTF) was measured with the slanted sharp-edge object under RQA5 technique as it described in the International Electrotechnical Commission 62220-1 standard (high voltage 70 kVp, additional aluminium filter 21 mm) for images with compensated dark currents and adjusted sensitivity of detector elements. The 10% level of the calculated MTF function has spatial resolution within 2 - 3 pair of lines per mm for both vertical and horizontal orientation.

关键词： Linear Array gallium arsenide Calibration Dark Current Sensitivity Modular Transfer Function Normalized Noise Power Spectrum

Determination of Band Structure of gallium-arsenide and Aluminium-arsenide Using Density Functional Theory

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Computational Chemistry 2016年第3期4卷 73-82页

作者： J. A. Owolabi M. Y. Onimisi S. G. Abdu G. O. Olowomofe Department of Physics Nigerian Defence Academy Kaduna Nigeria Department of Physics Kaduna State University Kaduna Nigeria

This research paper is on Density Functional Theory (DFT) within Local Density Approximation. The calculation was performed using Fritz Haber Institute Ab-initio Molecular Simulations (FHIAIMS) code based on numerical atomic-centered orbital basis sets. The electronic band structure, total density of state (DOS) and band gap energy were calculated for gallium-arsenide and Aluminium-arsenide in diamond structures. The result of minimum total energy and computational time obtained from the experimental lattice constant 5.63 A for both gallium arsenide and Aluminium arsenide is -114,915.7903 eV and 64.989 s, respectively. The electronic band structure analysis shows that Aluminium-arsenide is an indirect band gap semiconductor while gallium-arsenide is a direct band gap semiconductor. The energy gap results obtained for GaAs is 0.37 eV and AlAs is 1.42 eV. The band gap in GaAs observed is very small when compared to AlAs. This indicates that GaAs can exhibit high transport property of the electron in the semiconductor which makes it suitable for optoelectronics devices while the wider band gap of AlAs indicates their potentials can be used in high temperature and strong electric fields device applications. The results reveal a good agreement within reasonable acceptable errors when compared with the theoretical and experimental values obtained in the work of Federico and Yin wang [1] [2].

关键词： FHI-Aims Local Density Approximation Band Structure Energy Band Gap Density of State gallium arsenide and Aluminium arsenide

A Miniaturized Bandwidth Reconfigurable Bandpass Chip Filter with Semi-lumped Topology and GaAs pHEMT Technology

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Chinese Journal of Electronics 2021年第1期30卷 192-198页

作者： LI Linqing ZHU Haoran NING Xingyu LI Zunwen WU Xianliang Key Lab of Intelligent Computing and Signal Processing Ministry of Education Anhui University

A miniaturized reconfigurable bandpass chip filter with semi-lumped topology and gallium arsenide pseudomorphic High electron mobility transistor（GaAs pHEMT） technology is proposed. Semi-lumped topology is employed to instead the traditional lumped inductor with microstrip transmission line, which can reduced the size of the tunable filter significantly. Three-order series and shunt resonated bandpass filter is implemented with shorted stubs and metal-insulator-metal capacitors. Two transmission zeros are introduced with the series resonator and the shunted GaAs FET. By tuning the gate bias circuit of the FET, the capacitance of the series resonator is changed and the bandwidth of the filter is adjusted correspondingly. An equivalent circuit model is developed to interpret the mechanism of the proposed filter circuit. A reconfigurable on chip filter sample operated at 10 GHz is fabricated to validate the design. Two fractional bandwidth of 14.3% and 23.5% are tuned with bias voltage of the FET, while insertion loss of 2.4 d B and 2.2 d B are observed with the filter, respectively. The area of the chip filter is 0.86 × 0.96 mm2and is equivalent to an electrical length of 0.08 × 0.09λg2at center frequency. Measurement results agree well with the simulation ones.

关键词： gallium arsenide tunable filter transmission zeros equivalent circuit model resonator filters shunted FET III-V semiconductors miniaturized bandwidth reconfigurable bandpass chip filter MIM devices microstrip transmission line chip filter sample shunt resonated bandpass filter metal-insulator-metal capacitors semilumped topology loss 2.4 dB gallium arsenide pseudomorphic High electron mobility transistor technology insertion loss filter circuit integrated circuit design GaAs integrated circuit manufacture frequency 10.0 GHz pHEMT technology microwave filters loss 2.2 dB HEMT integrated circuits series resonator miniaturized reconfigurable bandpass chip filter band-pass filters

Analysis of silicon-based integrated photovoltaic–electrochemical hydrogen generation system under varying temperature and illumination

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Journal of Energy Chemistry 2017年第1期26卷 72-80页

作者： Vishwa Bhatt Brijesh Tripathi Pankaj Yadav Manoj Kumar Department of Solar Energy School of TechnologyPandit Deendayal Petroleum UniversityGandhinagar 382007India Department of Science School of TechnologyPandit Deendayal Petroleum UniversityGandhinagar 382007India Department of Electrical Engineering Incheon National UniversityIncheon 406772Republic of Korea

Last decade witnessed tremendous research and development in the area of photo-electrolytic hydrogen generation using chemically stable nanostructured photo-cathode/anode materials. Due to intimately coupled charge separation and photo-catalytic processes, it is very difficult to optimize individual components of such system leading to a very low demonstrated solar-to-fuel efficiency (SFE) of less than 1%. Recently there has been growing interest in an integrated photovoltaic–electrochemical (PV–EC) system based on GaAs solar cells with the demonstrated SFE of 24.5% under concentrated illumination condition. But a high cost of GaAs based solar cells and recent price drop of poly-crystalline silicon (pc-Si) solar cells motivated researchers to explore silicon based integrated PV–EC system. In this paper a theoretical framework is introduced to model silicon-based integrated PV–EC device. The theoretical framework is used to analyze the coupling and kinetic losses of a silicon solar cell based integrated PV–EC water splitting system under varying temperature and illumination. The kinetic loss occurs in the range of 19.1%–27.9% and coupling loss takes place in the range of 5.45%–6.74% with respect to varying illumination in the range of 20–100 mW/cm2. Similarly, the effect of varying temperature has severe impact on the performance of the system, wherein the coupling loss occurs in the range of 0.84%–21.51% for the temperature variation from 25 to 50 °C. © 2016 Science Press

关键词： Electrochemical cells Electrochemical impedance spectroscopy gallium arsenide Hydrogen production Nanostructured materials Polysilicon Semiconducting gallium Silicon Silicon solar cells Solar power generation

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High Power 170 GHz Frequency Doubler Based on Ga As Schottky Diodes

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Chinese Journal of Electronics 2022年第3期31卷 547-554页

作者： TIAN Yaoling HE Yue HUANG Kun JIANG Jun LIN Changxing ZHANG Jian Microsystem and Terahertz Research Center China Academy of Engineering Physics Institute of Electronic Engineering China Academy of Engineering Physics School of Electronic Science and Engineering University of Electronic Science and Technology of China

The research on high power 170 GHz frequency doubler based on the Ga As Schottky diodes is proposed in this paper. This basic doubler cell is developed with a 50-μm-thick, 600-μm-wide, and 2-mm-long Al N substrate with high thermal conductivity to reduce the thermal effect. Besides, power combined frequency doubler has been fabricated to improve the power capacity by a factor of two. Great agreement has been achieved between the simulated results based on electrothermal model and measured performances. At room temperature, the 3 d B bandwidth of the single doubler based on Ga As Schottky diodes is 11.8% over the frequency range from 160 to 180 GHz with pumping power of 150 to330 m W. And the peak efficiency of the doubler is measured to be 33.1%, while the maximum output power is101.7 m W at 174.08 GHz. As for power combined circuit,the best efficiency is 30.1% with a related output power of204.6 m W. The proposed methods of developing high power multipliers can be applied in higher frequency band in the future.

关键词： basic doubler cell gallium arsenide electro-thermal model high power multipliers power combined circuit high thermal conductivity power capacity wide band gap semiconductors III-V semiconductors millimetre wave frequency convertors aluminium compounds Schottky diodes power combined frequency doubler pumping power thermal effect frequency multipliers high power frequency doubler thermal conductivity

Design and Analysis of a 0.01-to-6GHz 31dBm-P1dB 31.5%-PAE Distributed Power Amplifier in 0.25-μm GaAs Technology

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Chinese Journal of Electronics 2021年第3期30卷 549-555页

作者： MENG Fanyi LIU Cha HU Jianquan MOU Shouxian MA Kaixue School of Microelectronics Tianjin University School of Physics University of Electronic Science and Technology of China Smarter Micro Company

This paper presents the design and analysis of a distributed power amplifier with 6-d B bandwidth from 10 MHz to 6 GHz. To meet the stringent targeted specification, the concurrent design and analysis are carefully performed with optimizations in both passive and active devices. The gate capacitive division technique is proposed and proven theoretically of bandwidth extension effect and power efficiency enhancement. To validate the theory, a prototype is designed in a 0.25-μm Ga As technology. The fabricated amplifier chip is packaged in an evaluation cavity of SMA connectors. The measurement shows an average power gain of 15 d B, OP1 d Band PSAT of 31 d Bm and 32.6 d Bm at 3 GHz, and PAE at OP1 d Band PSAT points are 31.5% and 43.7% respectively. To the best of authors’ knowledge, the amplifier achieves the highest Power-added efficiency(PAE) among the similar Ga As amplifiers.

关键词： gallium arsenide III-V semiconductors gate capacitive division technique evaluation cavity microwave amplifiers bandwidth extension effect fabricated amplifier chip power efficiency enhancement network synthesis distributed amplifiers frequency 10.0 MHz to 6.0 GHz efficiency 31.5 percent active devices network analysis average power gain passive devices SMA connectors electric connectors circuit optimisation distributed power amplifier UHF power amplifiers GaAs GaAs technology power-added efficiency GaAs amplifiers size 0.25 mum concurrent design

Synthesis and Photoluminescence Properties of GaAs Nanowires Grown on Fused Quartz Substrates

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Chinese Physics Letters 2014年第5期31卷 100-103页

作者：赵玉峰李新化史同飞王文博周步康段花花曾雪松李宁王玉琦 Key Laboratory of Material Physics Institute of Solid State Physics Chinese Academy of Sciences Hefei 230031

GaAs nanowires are synthesized on fused quartz substrates by using molecular beam epitaxy via a vapor-liquidsolid mechanism with gold as the catalyst. High resolution-transmission electron microscopy is used to probe crystal quality and growth direction. Miero-photolumineseenee measurements are carried out to examine the optical properties of GaAs NWs. The low-temperature photoluminescenee （PL） emission of nanowires （NWs） has a peak at 1.513eV, 2meV lower than the zinc blende GaAs free exciton energy. The temperature-dependent band gap of NWs is seen to be somewhat different from that observed in bulk OaAs, and the PL rapidly quenches above 150K, with an activation energy of 6.3meV reflecting the presence of the longitudinal twins＇ structure.

关键词： gallium arsenide