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Evolution of surface morphology and photoluminescence characteristics of 1.3-μm In_(0.5)ga_(0.5)As/gaAs quantum dots grown by molecular beam epitaxy

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Chinese Optics Letters 2009年第1期7卷 52-55页

作者：魏全香任正伟贺振宏牛智川 Department of Physics Shanxi University Institute of Semiconductors Chinese Academy of Sciences

Evolution of surface morphology and optical characteristics of 1.3-μm In0.5ga0.5As/gaAs quantum dots （QDs） grown by molecular beam epitaxy （MBE） are investigated by atomic force microscopy （AFM） and photoluminescence （PL）. After deposition of 16 monolayers （ML） of In0.5ga0.5As, QDs are formed and elongated along the [120] direction when using sub-ML depositions, while large size IngaAs QDs with better uniformity are formed when using ML or super-ML depositions. It is also found that the larger size QDs show enhanced PL efficiency without optical nonlinearity, which is in contrast to the elongated QDs.

关键词： gaAs As/gaAs quantum dots grown by molecular beam epitaxy Evolution of surface morphology and photoluminescence characteristics of 1.3 ga m In QDs

Model for increased efficiency of CIGS solar cells by a stepped distribution of carrier density and ga in the absorber layer

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Science China(Physics,Mechanics & Astronomy) 2013年第8期56卷 1533-1541页

作者： SHARBATI Samaneh KESHMIRI Sayyed-Hossein Department of Electrical Engineering Ferdowsi University of Mashhad

In this paper, several structures for multilayer Cu(In1-xgax) Se2 (CIGS) thin film solar cells are proposed to achieve high conversion efficiency. All of the modeling and simulations were based on the actual data of experimentally produced CIGS cells reported in the literature. In standard CIGS cells with a single absorber layer, the effects of acceptor density and ga content on device performance were studied, and then optimized for maximum conversion efficiency. The same procedure was performed for cells with two and three sectioned CIGS absorber layers in which Cu and/or ga contents were varied within each consecutive section. This produces an internal additional electric field within the absorber layer, which resulted in an increase in carrier collection for longer wavelength photons, and hence, improvement in the conversion efficiency of the cell. An increase of approximately 3% in efficiency is predicted for cells with two layer absorbers. For multilayer cells in which Cu and ga distribution were stepped simultaneously, the improvement could be approximately 3.5%. This improvement is due to; enhanced carrier collection for longer-wavelength photons, and reduced recombination at the heterojunction and back regions of the cell. These results are confirmed by the physics of the cells.

关键词：薄膜太阳能电池载流子收集 CIGS 密度分布吸收层 ga GS型模型

Single-mode hybrid Al ga In As/Si octagonal-ring microlaser with stable output

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Chinese Optics Letters 2016年第3期14卷 55-58页

作者：隋少帅唐明英杨跃德肖金龙杜云黄永箴 The State Key Laboratory on Integrated Optoelectronics Institute of Semiconductors Chinese Academy of Sciences

Hybrid octagonal-ring microlasers are investigated for realizing a stable output from a silicon waveguide based on a two-dimensional simulation. The inner radius of the ring is optimized to achieve single-mode and low-threshold operation. Using the divinylsiloxane-benzocyclobutene （DVS-BCB） bonding technique, a hybrid A1gaInAs/Si octagonal-ring microlaser vertically coupled to a silicon waveguide is fabricated with a side length of 21.6 pm and an inner radius of 15 pm. A single transverse-mode operation is achieved with a threshold current density of 0.8 kA/cm2 and a side-mode suppression ratio above 30 dB, and a stable output from the lower silicon waveguide is obtained.

关键词： mode In ring Single-mode hybrid Al ga In As/Si octagonal-ring microlaser with stable output As Al ga

High-Performance In0.23ga0.77As Channel MOSFETs with High Current Ratio Ion/Ioff Grown on Semi-insulating gaAs Substrates by MOCVD

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Chinese Physics Letters 2015年第3期32卷 121-123页

作者：孔祥挺周旭亮李士颜乔丽君刘洪刚王圩潘教青 Key Laboratory of Semiconductor Materials Science Institute of Semiconductors Chinese Academy of Sciences Beijing 100083 Microwave Device and IC Department Institute of Microeleetronics Chinese Academy of Sciences Beijing 100029

We demonstrate high-performance In0.23 ga0.77 As channel metal-oxide-semiconductor field-effect transistors （ MOS- FETs） with high on-current to off-current （Ion/Ioff） ratio grown on semi-insulating gaAs wafers by metal-organic chemical vapor deposition （MOCVD）. The 2μm channel-length devices exhibit a peak extrinsic transeonductance of 150 mS/mm and a drain current up to 500 mA/mm. The maximum effective mobility is 1680 cm2/Vs extracted by the split C-V method. Furthermore, the Ion/Ioff ratio is significantly improved from approximately 4.5 × 10^3 up to approximately 4.32 × 10^4 by controlling the etch thickness of In0.49ga0.51P, The high drain current and high Ion/Ioff ratio of the In0.23ga0.77As channel MOSFETs are achieved due to the high effective mobility and the low gate leakage current density.

关键词： As Channel MOSFETs with High Current Ratio I MOSFET ga Grown on Semi-insulating gaAs Substrates by MOCVD off

Observation of Self-Frequency Doubling in Diode-Pumped Mode-Locked Nd-Doped La3ga5SiO14 Laser

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Chinese Physics Letters 2015年第1期32卷 67-69页

作者：刘家兴王兆华田文龙王庆张治国魏志义于浩海张怀金王继扬 Beijing National Laboratory for Condensed Matter Physics and the Institute of PhysicsChinese Academy of Sciences School of Physics and Optoelectronic Engineering Xidian University Department of Opto-Electronics Beijing Institute of Technology State Key Laboratory of Crystal Material and Institute of Crystal Material Shandong University

A diode-pumped passively mode-locked Nd-doped La3ga5SiO14 （Nd：LGS） laser is realized by using a semicon- ductor saturable absorber mirror. With the pump power of 2 W, we obtain a 532nm self-frequency doubling （SFD） laser together with a lO.9ps fundamental laser at the repetition rate of 173.7MHz. To the best of our knowledge, it is the first time for self-frequency doubling in the diode-pumped mode-locked Nd：LGS laser. Benefited from the diode lasers and its self-frequency doubling property, Nd：LGS could be a potential candidate for compact, stable and cheap ultrafast green laser sources.

关键词： LGS Nd SFD ga

Modulating the threshold voltage of oxide nanowire field-effect transistors by a ga^＋ ion beam

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Nano Research 2014年第11期7卷 1691-1698页

作者： Wenqing Li Lei Liao Xiangheng Xiao Xinyue Zhao Zhigao Dai Shishang Guo Wei Wu Ying Shi Jinxia Xu Feng Ren Changzhong Jiang Department of Physics and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education Wuhan UniversityWuhan 430072 China

在这份报纸，我们报导一个方法改变 SnO 的阀值电压 2 并且在里面 2 O 由 ga 的 3 只 nanowire 晶体管+离子照耀。不同于在更早的报告的结果， SnO 的阀值电压 2 并且在里面 2 O 在在 ga 以后的否定的门电压方向的 3 nanowire 地... 详细信息

在这份报纸，我们报导一个方法改变 SnO 的阀值电压 2 并且在里面 2 O 由 ga 的 3 只 nanowire 晶体管+离子照耀。不同于在更早的报告的结果， SnO 的阀值电压 2 并且在里面 2 O 在在 ga 以后的否定的门电压方向的 3 nanowire 地效果晶体管(联邦货物税)移动+离子照耀。更小的阀值电压，由 ga 完成了 + 离子照耀，为高效、低电压的操作被要求。阀值电压移动能被归因于 ga 引起的表面缺点的降级 + 离子照耀。在照耀以后，当前的开／关比率稍微衰退，但是离 10 仍然靠近 6 。结果显示那 ga + 离子横梁照耀在改进氧化物 nanowire 联邦货物税的表演起一个重要作用。

关键词：阈值电压漂移场效应晶体管离子束辐照纳米线氧化物 ga In2O3 调制

On-line Optimization of Biomimetic Undulatory Swimming by an Experiment-based Approach

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Journal of Bionic Engineering 2014年第2期11卷 213-225页

作者： Chunlin Zhou Kin Huat Low Department of Control Science and Engineering Zhejiang University Hangzhou 310027 P. R. China School of Mechanical and Aerospace Engineering Nanyang Technological University Singapore 639798 Singapore

An experiment-based approach is proposed to improve the performance of biomimetic undulatory locomotion through on-line optimization. The approach is implemented through two steps：（1） the generation of coordinated swimming gaits by artificial Central Pattern Generators （CPGs）; （2） an on-line searching of optimal parameter sets for the CPG model using Genetic Algorithm （ga）. The effectiveness of the approach is demonstrated in the optimization of swimming speed and energy effi- ciency for a biomimetic fin propulsor. To evaluate how well the input energy is converted into the kinetic energy of the pro- pulsor, an energy-efficiency index is presented and utilized as a feedback to regulate the on-line searching with a closed-loop swimming control. Experiments were conducted on propulsor prototypes with different fin segments and the optimal swimming patterns were found separately. Comparisons of results show that the optimal curvature of undulatory propulsor, which might have different shapes depending on the actual prototype design and control scheme. It is also found that the propulsor with six fin segments, is preferable because of hizher speed and lower energy efficiency.

关键词： robotic fish biomimetics locomotion optimization CPG ga

Advanced optimization of gas turbine aero-engine transient performance using linkage-learning genetic algorithm:PartⅡ,optimization in flight mission and controller gains correlation development

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Chinese Journal of Aeronautics 2021年第4期34卷 568-588页

作者： Yinfeng LIU Soheil JAFARI Theoklis NIKOLAIDIS Aero Engine Test Department of Hunan Aviation Powerplant Research Institute AECCZhuzhou 412002China Centre for Propulsion Engineering School of Aerospace Transport and Manufacturing(SATM)Cranfield UniversityCranfield MK430ALUK

PartⅠhas illustrated the procedures to apply the Linkage Learning Genetic Algorithm(LLga)in gas Turbine Engine(GTE)controller gains tuning and generated the optimization results for runway conditions from idle to takeoff.However,the total pressure and temperature of the engine inlet vary as the changing of altitude and Mach number,which would lead to the variation in fuel flow supply regulation.As a result,the optimized gains in runway might not be suitable for other flight conditions.In order to maintain the optimal control performance,the GTE controller gains should be adjusted according to the flight conditions.This paper extends the application of the LLga method to other flight conditions and then simulates a complete flight mission with different gains and weather condition configurations.For this purpose,the control parameters in the Simulink model of the GTE controller are first corrected by the weather condition in altitude.Then,a typical flight mission is defined and divided into different flight segments based on the altitude and Mach number configuration.One representative point is selected from each segment as the datum point for optimization process.After this step,the LLga method is used to find the best gains combinations for different flight conditions and the differences in optimization effects for different flight conditions are analyzed subsequently.The simulation results show that the optimization effect of the control performance of each flight condition is dependent on the value of(θδ)~(1/2)and the optimal K_(pla)in some flight conditions is approximately equal to p hd times of the Kplavalue in sea level standard condition.Finally,the complete flight mission is simulated with different gains and weather condition configurations.The simulation results show that the engine performance has been greatly improved after optimization by LLga in the transient state and the high altitude conditions.In other steady states,the optimization effect is not very obvious.

关键词： Aeroengine control Control optimization Flight condition Flight mission simulation ga GTE LLga Min-Max controller Robustness

Towards high-mobility In2xga2-2xO3 nanowire field-effecttransistors

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Nano Research 2018年第11期11卷 5935-5945页

作者： Ziyao Zhou Changyong Lan SenPo Yip Renjie Wei Dapan Li Lei Shu Johnny C. Ho Department of Materials Science and Engineering City University of Hong Kong Kowloon Hong Kong 999077 China School of Optoelectronic Science and Engineering University of Electronic Science and Technology of China Chengdu 610054 China Shenzhen Research Institute City University of Hang Kong Shenzhen S 18057 China State Key Laboratory of Millimeter Waves City University of Hang Kong Kowloon Hang Kong 999077 China

Recently, owing to the excellent electrical and optical properties, n-type In2O3 nanowires (NWs) have attracted tremendous attention for application in memory devices, solar cells, and ultra-violet photodetectors. However, the relatively low electron mobility of In2O3 NWs grown by chemical vapor deposition (CVD) has limited their further utilization. In this study, utilizing in-situ ga alloying, highly crystalline, uniform, and thin In2xga2−2xO3 NWs with diameters down to 30 nm were successfully prepared via ambient-pressure CVD. Introducing an optimal amount of ga (10 at.%) into the In2O3 lattice was found to effectively enhance the crystal quality and reduce the number of oxygen vacancies in the NWs. A further increase in the ga concentration adversely induced the formation of a resistive β-ga2O3 phase, thereby deteriorating the electrical properties of the NWs. Importantly, when configured into global back-gated NW field-effect transistors, the optimized In1.8ga0.2O3 NWs exhibit significantly enhanced electron mobility reaching up to 750 cm2·V–1·s–1 as compared with that of the pure In2O3 NW, which can be attributed to the reduction in the number of oxygen vacancies and ionized impurity scattering centers. Highly ordered NW parallel arrayed devices were also fabricated to demonstrate the versatility and potency of these NWs for next-generation, large-scale, and high-performance nanoelectronics, sensors, etc.

关键词： In 2 O 3 In 2 x ga 2−2 x O 3 nanowire chemical vapor deposition mobility oxygen vacancy