在Ge和GaAs衬底上气相生长ZnSe异质结外延膜

用气相外延方法在Ge和GaAs衬底上成功地生长出性能良好的异质外延薄膜,经降阻掺杂制成异质P—N〔(p)Ge—ZnSe(n)和(p)GaAs—Znse(n)〕结,克服Ⅱ—Ⅵ族化合物无法做成P—N结的“自补偿”效应,通过X射线分析、劳厄照相和I—V、C—V测试表明,ZnSe 外延薄膜质量较好,可做为重要的光学材料.     

IMEC采用机械叠层方式制造出GaAs／Ge多结太阳能电池

IMEC已经成功的采用机械叠层的方法在锗电池上集成了GaAs电池,朝转化效率高于40％的三结太阳能电池迈进了一步。与单光刻多结电池不同,机械叠层结构无需进行电流匹配和晶格匹配。     

四结叠层太阳电池中AlGaAs/GaAs隧穿结的特性和表现

III-V族化合物叠层太阳电池是具有超高转换效率的第三代新型太阳电池。四结叠层电池GaInP/GaAs/InGaAs/Ge,各子电池的带隙分别为1.8, 1.4, 1.0, 0.7(ev)。为了使各子电池之间电流匹配,在各子电池之间以隧穿结互相连接。本文主要探索研究了四结叠层电池GaInP/GaAs/InGaAs/Ge隧穿结的特性,三个隧穿结的材料选取,探讨了隧穿结对整体叠层电池的特性的补偿作用,对各子电池电流密度的影响,以及在此基础上对整体电池效率的增加。选用AlGaAs/GaAs作为隧穿结运用PC1D进行电池的整体模拟仿真,得到各子电池电流密度分别为16.02mA/cm²,17.12 mA/cm²,17.75 mA/cm²,17.45 mA/cm²,电池在AM0下的开路电压Voc为3.246V,转换效率为33.9%。     

五结太阳能电池设计与模拟

设计了与太阳光谱更匹配的五结太阳能电池(Al)GaInP/AlGa(In)As/(In)GaAs/GaInAsN/Ge,并首次应用APSYS软件对其电特性进行了模拟。与四结太阳能电池和传统的InGaP/GaAs/Ge结构进行对比,结果表明该结构各结电流更加匹配,获得了较高的转换效率。     

聚光光伏技术及研究进展

<正>聚光光伏技术是指利用光学元件将太阳光汇聚后,通过高转化效率的光伏电池(GaAs基)直接转换为电能的技术,被认为是太阳能发电未来发展趋势的第三代技术,即聚光光伏(CPV)。1.聚光光伏技术概述GaAs基太阳能电池可分为单结和多结叠层式太阳能电池两类。GaAs、Ge单结太阳电池理论效率27%,实验室效率达到     

连续激光对三结GaAs电池的损伤效应北大核心CSCD

在空气中和真空中,利用波长为1070nm的连续(CW)激光辐照三结砷化镓(GaAs)太阳电池,通过测试激光辐照前后电池的电流-电压曲线,并利用激光诱导电流(LBIC)成像系统和X射线光电子能谱仪(XPS),研究了三结GaAs太阳电池的损伤情况。结果表明,当激光功率密度为8.4 W/cm2、辐照时间为10s时,在空气中,底电池Ge熔融短路;在真空中,顶电池Ga0.5In0.5P和底电池Ge均发生短路,说明三结GaAs太阳电池的底电池最容易受到破坏,且电池在真空中比在空气中更容易受到损伤。该研究结果可为三结GaAs太阳电池的激光无线能量传输和损伤机理的研究提供一定的参考。     

三组三元合金异质结的价带带阶

采用基于LMTO－ASA的平均键能计算方法和原子集团展开方法，研究了三组典型的晶格匹配三元合金异质结（GaAs）x（Ge2）1-x／GaAs，（AlAs）x（Ge2）1-x／GaAs和AlxGa1-xAs／GaAs的价带带阶△Ev（x）值。研究表明：AlxGa1-xAs／GaAs异质结的Mv（x）值随合金组分x的变化接近于线性；（GaAs）x（Ge2）1-x／GaAs和（AlAs）x（Ge2）1-x／GaAs的△Ev（x）值随合金组分x的变化是非线性的。△Ev（x）的理论计算值与实验结果相当符合。     

GaAs太阳电池的体电阻及旁路漏电对电池结特性的影响

复合电流是液相外延GaAs太阳电池暗电流的主要成分。扫描电镜观察表明,旁路电流主要来源于太阳电池结区的杂质。串联电阻主要来源于电池p型GaAs层的薄层电阻及正面电极的体电阻。串联电阻降低了电池的短路电流,旁路电阻降低了电池的开路电压。减小电池p-GaAs层的薄层电阻是提高电池效率的重要途径。     

GaInP2/Ge异质结外延材料特性分析

研制了一种基于Ge衬底的异质结热光伏(TPV)电池 ,并且在Ge衬底上用金属有机化学气相沉积(MOCVD)法外延单晶材料GaInP₂和GaAs,对GaInP₂/Ge异质结界面进行了断面扫描电镜(SEM)、X射线衍射(XRD)、电化学电 容电压(ECV)和光致荧光(PL)谱的测试分析,研究了基于 Ge衬底的异质结n-GaInP₂/p-Ge界面的结构、光学和电学特性,得到了高质量、宽禁带 的单晶外延层,与Ge衬底晶格匹配良好,利于更多光子进入到吸收层,为制备高效率TPV电 池打下良好基础。     

三波长激光照射下砷化镓聚光电池光电转换效率的研究

三结砷化镓叠层电池(InGaP/GaAs/Ge)耐强光、光电转换效率高且温度特性好,是激光无线电能传输系统中光电转换组件的理想材料.基于三结砷化镓叠层电池的光谱响应曲线,以532、808和980 nm三种波长激光组合入射,在保证入射总功率密度为2 W/cm2的条件下,研究了三种波长入射激光的不同功率配比对其光电转换效率的影响.结果表明,在532、808和980 nm三种波长入射激光功率配比为7:8:5时,光电转换效率最高,为33.549％.该研究对提高三结砷化镓电池的转换效率有一定的应用价值.     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks