GaAs多量子阱的光电流谱

在Ｔ＝７７Ｋ,测量了ＧａＡｓ多量子阱的光电流,发现在ｖ＝１３１２ｃｍ＾－１附近存在一个强电流峰,并且在这强电流峰附近的高波数区还有几个弱峰,强电流峰是量子阱中基态电子向第一激发态跃迁形成的,而弱峰与最子阱势垒以上的电子干涉有关。     

一种具有GaInAsN/GaAs量子阱结构的三结太阳能电池的设计

该文使用传输矩阵法分析了GaInAsN/GaAs量子阱对电子的透射情况,并使用crosslight软件对GaInAsN/GaAs量子阱太阳能电池的伏安特性进行了数值模拟和分析。初步讨论了量子阱的阱宽和垒厚的变化对量子阱电池伏安特性的影响.模拟结果发现垒厚32nm、阱宽7nm的量子阱光伏性能表现良好。作为有源区,当将该量子阱加入到GaAs子电池中,InGaP/GaAs/Ge三结电池在AM0下的短路电流密度达到19.81mA/cm2,比未使用量子阱有源区的三结电池提高了20%。     

LP-MOCVD生长大功率InGaAsP/GaAs量子阱激光器

设计并利用LP－MOCVD生长了InGaAsP/GaAs分别限制单量子阱结构,采用无铝的InGaP做光学包层。腔面未镀膜情况下,测试10支条宽100μm,腔长1mm的激光器样品,连续输出功率超过1W,阈值电流密度为330～490A/cm2,外微分量子效率为55％～78％,中心发射波长为(808±3)nm。     

连续输出20WAlGaAs／GaAs量子阱激光二极管线列阵

采用ＭＯＣＶＤ实现了ＡｌＧａＡｓ／ＧａＡｓ量子阱结构，获得了连续输出２０Ｗ激光二极管线列阵，线列阵长度１．０ｃｍ，激射波长８０８±４ｎｍ。     

1．52μmInGaAsP／InP分别限制量子阱激光器

报导了在６００℃生长温度下以三甲基镓（ＴＭＧａ）和三甲基铟（ＴＭＩｎ）为Ⅲ族源，用低压金属有机气相沉积（ＬＰ－ＭＯＣＶＤ）技术生长出的高质量１．６０μｍ和１．３μｍＩｎＧａＡｓＰ材料，以及在其分别限制量子讲结构生长的情况下，用质子轰击方法制得的条形结构量子阱激光器。该激光器在室温下直流阈值电流为１００ｍＡ。     

980nm InGaAs／GaAs／AlGaAs应变量子阱激光器

报导了脊形波导ＩｎＧａＡｓ／ＧａＡｓ／ＡｌＧａＡｓ应变量子阱激光器的特性和实验结果，激光器阀值电流最低为９ｍＡ，典型值为１５ｍＡ，线性输出光功率大地１２０ｍＷ，微分量子效率典型值为６０％，５０℃，８０ｍＷ恒定功率条件下老化实验结果表明；该条件下激光器寿命超过１０００小时。     

高功率GaAs/GaAlAs单量子阱远结激光器

通过对５０余只８０８ｎｍ的ＧａＡｓ／ＧａＡｌＡｓ高功率单量子阱远结半导体激光器的老化实验观测,在老化初期（前５２０ｈ）,阈值电流随老化时间的延长而下降,下降幅度高达５７ｍＡ,从１０００ｈ多的恒流电老化结果可以看出,器件的输出光功率在老化初期有所上升,随后,表现出按指数规律缓慢下降的行为。初步实验结果表明器件具有长寿命的潜力。     

介电常数失配对InAs/GaAs应变量子阱中浅施主结合能的影响

研究了介电常数失配对ＩｎＡｓ／ＧａＡｓ应变量子阱中浅施主结合能的影响。在有效质量近似下，利用变分方法计算了结合能随阱宽和杂质位置的变化。计算结果表明，介电常数失配对结合能的影响很大，这与前人的工作相符合，但晶格常数失配产生的应变对结合能的影响很小，并可以忽略。     

量子阱晶体管研究获突破

英特尔公司与QinetiQ公司在基于锑化铟（InSb）技术的量子阱（quantum-well）晶体管的预研领域取得重大突破，有望将摩尔定律（Moore’s Law）的效用拓展到下一个十年。     

Transient-grating Studies in GaAs/GaAlAs Multiple Quantum Wells

Abstract

We report degenerate four-wave mixing experiments at room temperature, using a three-beam geometry and sub-picosecond laser to study GaAs/GaAlAs multiple quantum well material. Diffraction efficiencies and grating decay times for two samples of different carrier lifetimes have been measured in the spectral region corresponding to excitonic resonances. The measurements provide values of the nonlinear refractive index per carrier pair (n _eh) deriving from the excitonic saturation, and also the recombination times and diffusion coefficients for the samples.     

Optical and Magnetic Properties of Ten-Period InGaMnAs/GaAs Quantum Wells

Ten layers of InGaMnAs/GaAs multiquantum wells (MQWs) structure were grown on high resistivity (100) p-type GaAs substrates by molecular beam epitaxy (MBE). A presence of the ferromagnetic structure was confirmed in the InGaMnAs/GaAs MQWs structure, and have ferromagnetic ordering with a Curie temperature, T _C=50 K. It is likely that the ferromagnetic exchange coupling of the sample with T _C=50 K is hole-mediated resulting in Mn substituting In or Ga sites. PL emission spectra of the InGaMnAs MQWs sample grown at a temperature of 170 °C show that an activation energy of the Mn ion on the first quantum confinement level in InGaAs QW is 32 meV and impurity Mn is partly ionized. The fact that the activation energy of 32 meV of Mn ion in the QW is lower than an activation energy of 110 meV for a substitutional Mn impurity in GaAs, indicating an impurity band existing in the bandgap due to substitutional Mn ions.     

Zero-Magnetic-Field Spin Splitting of Conduction Subbands in InGaAs/InAlAs and GaAs/AlGaAs Quantum Wells

Zero-magnetic-field spin splitting in InGaAs/GaAs and GaAs/AlGaAs multiple quantum wells was investigated theoretically. The sp³s* empirical tight-binding method has been employed. It has been found that the splitting is much larger in InGaAs wells than that in GaAs wells. The origin of the splitting due to the structure inversion asymmetry was briefly discussed.     

Spin-Galvanic Effect in Quantum Wells

It is shown that a homogeneous nonequlibrium spin polarization in semiconductor hetero- structures results in an electric current. The microscopic origin of the effect is an inherent asymmetry of spin-flip scattering in systems with lifted spin degeneracy caused by k-linear terms in the Hamiltonian.     

Peculiarities of Silicon-Donor Ionization and Electron Scattering in Pseudomorphous AlGaAs/InGaAs/GaAs Quantum Wells with Heavy Unilateral Delta-Doping

The influence of the concentration of silicon donors on the electron-transport properties of pseudomorphous Al_0.25Ga_0.75As/In_0.2Ga_0.8As/GaAs quantum wells (QWs) in heterostructures with heavy unilateral δ-doping by Si atoms was studied in a broad temperature interval (2.1–300 K). High electron mobility (up to 35700 cm²/(V s)) at T = 4.2 K was observed at a 2D (sheet) electron density of 2 × 10¹² cm^–2 in the QW. A band mechanism limiting the ionization of donors at an increased level of doping is described. The nonmonotonic variation of electron mobility with increasing silicon concentration is explained. A growth in the mobility is related to increase in the Fermi momentum and screening, while the subsequent decay is caused by tunneling-induced degradation of the spacer layer with decreasing potential of the conduction band in the region of δ-Si layer. It is shown that the effect is not related to filling of the upper subband of dimensional quantization.     

Intraband Radiation Absorption by Free Holes in GaAs/InGaAs Quantum Wells with Allowance for Nonsphericity of the kP Hamiltonian

Technical Physics Letters - A system of Kane’s equations has been derived and solved with allowance for elastic stresses and nonsphericity of the kP Hamiltonian. On this basis, analytic...     

染料敏化太阳能电池的制作

主要讨论了染料敏化太阳能电池的制备过程,介绍了所做的一系列工艺优化工作,探讨了二氧化钛薄膜厚度、四氯化钛处理二氧化钛电极、大粒子散射层、酸预处理二氧化钛粉体对电池效率的影响.结果表明,用酸预处理二氧化钛粉体、用四氯化钛处理电极、在一定范围内增加电极的厚度和引入大粒子散射层均可提高电池效率.     

应变补偿1eV吸收带边GaInAsN/GaAs超晶格太阳能电池格层设计

本文采用计算超晶格电子态常用的Kronig-Penney模型和形变势理论,从理论上探讨了GaInNAs/GaAs超晶格能带系统的能带结构,计算得到了能带结构随各亚层参量变化的一般性规律、超晶格的能量色散关系、应变造成的影响以及不同亚层厚度的系统禁带宽度。计算了超晶格的阱层材料在不同的组分选择下,GaInAsN/GaAs超晶格吸收带边为1eV的超晶格相关参数的对应关系以及超晶格应变状态。计算表明采用高In低N的GaInNAs材料作为GaInNAs/GaAs超晶格的阱层时更有利于获得高质量且较厚的GaInNAs/GaAs超晶格有源区,并且此时可以获得较好的应变补偿;进一步对超晶格太阳能电池的内量子效率进行了模拟计算,分析了1eV吸收带边GaInAsN/GaAs超晶格太阳能电池对提高整体光电转换效率的可行性。     

GaAs光电阴极智能激活研究

研制了一套基于计算机控制的GaAs光电阴极智能激活系统,该系统可在计算机控制下严格按照标准工艺对GaAs光电阴极进行智能激活,并可在线测量阴极的光谱响应曲线.利用该系统分别进行了智能激活和人工激活实验,采集了激活过程中的光电流变化曲线,分析发现,和智能激活过程相比,由于人工激活过程出现了误操作,相邻光电流峰值间的差值下降很快,Cs、O交替的次数也较少.人工激活过程中Cs、O交替6次,光电流最大值为43μA,激活后GaAs光电阴极的积分灵敏度为796μA/lm.智能激活过程中Cs、O交替9次,光电流最大值为65μA,激活后GaAs光电阴极的积分灵敏度为1100μA/lm.