GaAs_(0.6)P_(0.4):Te深中心的电声耦合与晶格弛豫

用DLTS技术结合光电容定态谱、瞬态谱、OITS谱研究了GaAs_(0.6)P_(0.4):Te深中心的光电性质和电声耦合作用,在GaAs_(0.6)P_(0.4):Te中检测到两种深中心(A和B中心),表观热激活能分别为0.20和0.40eV,光离化阀值分别为0.60和1.31eV。详细研究了B中心的特性,测量了光离化截面谱的温度关系,发现有明显的声于展宽现象和晶格弛豫效应,并在低温(90K)观察到B中心的持续光电导效应。描绘出位形坐标图,说明了实验结果,较好地描述了B中心的特性,确认B中心属于DX中心。     

Zn_(0.04)Cd_(0.96)Te中深能级的红外光电导谱研究

应用红外光电导谱研究半绝缘p型Zn0.04Cd0.96Te中的深能级,在温度从4.2到165K范围内,观察到了位于0.24,0.34,0.38,0.47,0.55和0.80eV处6个光电导响应峰.结合4.2K下光致发光谱的测量结果以及对ZnxCd1-xTe中深能级发光光谱、深能级瞬态谱等已有的研究结果,对这些响应峰对应的深能级特性进行了讨论.     

GaAsP混晶中的DX中心

用高分辨率深能级瞬态谱、光照深能级瞬态谱及光电容谱方法,对不同组份的掺Te的GaAsP混晶进行了实验研究,结果表明,所有被测样品中同时存在三种施主深能级,其热发射激活能各为0.18,0.28,0.38eV.通过仔细测量与分析它们的电学和光学性质后,认为它们是由Te施主杂质形成的三种类DX中心,可能对应于Te运动会替位施主的不同原子构形. 关键词：     

相对论效应对Na原子激发态2p光电离过程的影响

在多组态Dirac-Fock相对论理论框架下,研究了入射光子能量为54eV时Na原子2p~63p激发态2p的光电离过程.结果表明:相对论效应对原子光电离过程有非常明显的影响;虽然相对论效应对相应电离能的影响有限,但可使光电子的强度分布产生实质性变化,从而使两激发态2p~63p(2P1/2,3/2)的光电子谱的结构完全不同;而在非相对论极限下,两初态2p~63p(2P1/2,3/2)的光电子谱几乎完全相同.该研究可为获得有关激发态光电离过程的相对论效应信息提供一种方法.     

氮化镓材料中深能级中心光离化谱测试与分析

设计了一种可用于测试氮化镓材料深能级中心光离化截面的光谱测试方法,该方法建立在使用PID技术控制氮化镓样品中光电流变化为恒定值的基础上,结合光电流测试、霍尔效应、光强度测试等实验手段给出深能级中心光离化截面的实际值。使用该方法得到的光离化截面测试误差同光电探测器对不同入射光子的响应能力有关,光离化截面测试误差随入射光子能量增加不断增大,在入射光子能量较高的情况下,光离化截面测试误差约为8%。对氮化镓材料深能级中心光离化谱分析发现,即使在入射光子能量小于深能级同导带之间能量差2.85eV的情况下,深能级中心仍能在一定程度上吸收该能量的入射光子,表明深能级中心缺陷同周围晶格产生一定程度的耦合。     

分子束外延生长GaAs/Si异质结电学特性的研究

利用样品Au-GaAs/p-Si的肖特基势垒二极管特性和深能级瞬态谱(DCTS),研究Si衬底上分子束外延生长的GaAs异质结的电学特性。I-V特性表明样品有大的漏电流存在,而快速热退火处理则能使样品I-V特性得以改善,并接近半绝缘GaAs(S.I.GaAs)上生长的Au-GaAs/S.I.GaAs样品的特性,它的来源不是热电子发射或产生-复合电流所引起,而可归结于缺陷参与的隧穿机制,它可通过快速热退火处理得以减小。DCTS谱表明在样品中可观察到Ec-0.41eV和Ec-0.57eV两个电子陷阱,前者可能 关键词：     

深能级对GaAs1-xPxLED老化过程的影响

用深能级瞬态谱(DLTS)研究了GaAs1-xPx LED在正向电压,I=100mA(J=250A/cm2)大电流下老化750小时左右的过程中深能级浓度、深度、俘获截面的变化。GaAs1-xPx LED中存在三个电子能级:△En1=(0.19±0.01)eV;△En2=(0.20±0.01)eV;△En3=(0.40±0.01)eV。发现老化之后△En1与△En2的能级密度变小,而△En3的能级宽度却有所增大。同时测量了它们的发光光谱、光通,C-V特性和I-V特性。讨论了深能级在GaAs1-xPx LED老化过程中对发光效率与退化特性的影响。认为△En1与△En2对GaAs1-xPx LED的发光效率与退化特性无影响,而△En3是限制GaAs1-xPx LED发光效率和退化特性的有效复合中心。     

证实GaAs中深能级陷阱发射到间接导带的极小的新技术

本文对具有深能级陷阱的肖特基势垒耗尽区的C-V特性提供了一种新的分析,得到了能带图中能级的绝对位置。发现了通常在气相外延GaAs中观察到的0.83±0.005eV电子陷阱位于Γ导带极小下0.543eV(240K)和0.537eV(120K)处。表明这些能级能发射电子到L极小,而且与这些极小有关的参数具有零的温度系数。这些中心的俘获截面是σ∽=(1.8±0.4)×10~(-14)cm~2,在120—240K整个温度区域有一个零的激活能。     

在透明衬底上制取高效率GaAsP发光二极管

市售的GaAsP发光二级管所发出的光仅占其内部所产生光量的2～4％。效率低的部分原因是由于光被较小的带隙过渡区和衬底所吸收。假如GaAsP生长在透明衬底上,从而使衬底和过渡区具有比GaAsP发射区更宽的带隙,则外量子效率可获得显著的提高。原则上诸如尖晶石、蓝宝石、GaP以及带隙比发光GaAsP更大的GaAsP材料都可用作衬底。虽然对于后两种材料都进行过研究, 但本文的结果都是用GaP作衬底制作的器件所得到的。 所研究过的第一种结构是在GaP(100)衬底上生长GaAs0.6P0.4。外延层组分从衬底的GaP开始逐渐变化到GaAs0.6P0.4,紧接着再生长5μ恒定组分的GaAs0.6P0.4。器件的几何构造是采用Zn扩散和光刻腐蚀的p-n结台面,顶部是Al欧姆接触,底部是能反射光的欧姆接触。然后经过锯割或划片把片子分成小块,由于GaAs0.6P0.4是直接带发射体。恒定组分区p-n结所产     

Z箍缩Al等离子体X辐射谱线的分离及电子温度的提取

以"强光一号"Z箍缩装置10174发次光谱诊断实验结果为例,描述了一种对Z箍缩等离子体X辐射光谱分离提纯、诊断的方法.对连续辐射谱和特征辐射线谱进行分离,并从连续辐射谱和特征辐射线谱中提取了等离子体电子温度信息.结果显示:等离子体连续谱主要由等离子体中心的高温区(Te=290.7 eV±1.2 eV)和温度较低的壳层区域(Te=95.3 eV±8.3 eV)两部分叠加而成;特征辐射线谱主要反映了等离子体中心的高温区信息,根据非局域热动平衡模型计算提取的电子温度约为299—313 eV,与连续谱诊断结果基本符合.     

Using the Hg_xMg_(1-x)Te ternary compound as a room temperature photodetector: The electronic structure,charge transport,and response function of the energetic electromagnetic radiation

In the present work, firstly, a first-principles study of the structural, electronic, and electron transport properties of the Hg_xMg_(1-x)Te(HMT) ternary compound is performed using the ABINIT package and the results are compared with Cd_(0.9)Zn_(0.1) Te(CZT) as a current room-temperature photodetector. Next, the response functions of Hg_(0.6)Mg_(0.4)Te and Cd_(0.9)Zn_(0.1)Te under electromagnetic irradiation with 0.05 Me V, 0.2 MeV, 0.661 MeV and 1.33 MeV energies are simulated by using the MCNP code. According to these simulations, the Hg_(0.6)Mg_(0.4)Te ternary compound is suggested as a good semiconductor photodetector for use at room temperature.     

Multilayer self-organization of InGaAs quantum wires on GaAs surfaces

Molecular-Beam Epitaxy growth of multiple In_0.4Ga_0.6As layers on GaAs (311)A and GaAs (331)A has been investigated by Atomic Force Microscopy and Photoluminescence. On GaAs (311)A, uniformly distributed In_0.4Ga_0.6As quantum wires (QWRs) with wider lateral separation were achieved, presenting a significant improvement in comparison with the result on single layer [H. Wen, Z.M. Wang, G.J. Salamo, Appl. Phys. Lett. 84 (2004) 1756]. On GaAs (331)A, In_0.4Ga_0.6As QWRs were revealed to be much straighter than in the previous report on multilayer growth [Z. Gong, Z. Niu, Z. Fang, Nanotechnology 17 (2006) 1140]. These observations are discussed in terms of the strain-field interaction among multilayers, enhancement of surface mobility at high temperature, and surface stability of GaAs (311)A and (331)A surfaces.     

离子注入GaAs的脉冲激光退火

利用沟道背散射、俄歇和X射线光电子能谱技术研究了Nd:YAG和红宝石脉冲激光退火的离子注入GaAs样品的表面性质。结果表明,对于这两种激光都存在一个从无定形向单晶转化的阈值能量,在阈值能量附近,没有明显的表面分解。高能量密度可引起明显的分解和损伤。利用热流理论计算了杂质的再分布。对于两种激光都得到了Te在GaAs中较高的替位率。 关键词：     

Normal-state hourglass dispersion of the spin excitations in FeSexTe(1-x)

We use cold neutron spectroscopy to study the low-energy spin excitations of superconducting (SC) FeSe0.4Te0.6 and essentially nonsuperconducting (NSC) FeSe0.45Te0.55. In contrast with BaFe2-x(Co,Ni)xAs2, where the low-energy spin excitations are commensurate both in the SC and normal state, the normal-state spin excitations in SC FeSe0.4Te0.6 are incommensurate and show an hourglass dispersion near the resonance energy. Since similar hourglass dispersion is also found in the NSC FeSe0.45Te0.55, we argue that the observed incommensurate spin excitations in FeSe(1-x)Tex are not directly associated with superconductivity. Instead, the results can be understood within a picture of Fermi surface nesting assuming extremely low Fermi velocities and spin-orbital coupling.     

Electrophysical properties and annealing of defects in nuclear transmutation-doped GaAs irradiated by H+ ions

A study has been made of the electrophysical characteristics of nuclear-transmutation-doped GaAs (NTDG) and GaAs doped with metallurgical impurities Sn, Te, Ge, and In, after irradiation by H⁺ ions at fluxes of up to 1.5·10¹⁶ cm^–2. It is shown that the changes in the GaAs produced by irradiation do not depend on the method used to dope the material and can be described on the basis of the known spectrum of E and H traps in GaAs. Crystals of GaAs annealed after irradiation display deep (P1–P3) traps, which are responsible for the high-temperature proton insulation GaAs.V. D. Kuznetsov Siberian Physicotechnical Institute at the State University, Tomsk. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 61–65, October, 1992.     

Ⅲ-Ⅴ族化合物半导体中的深能级杂质缺陷

本文综述了近十多年以来对Ⅲ-Ⅴ族化合物半导体中深能级杂质缺陷的研究工作。讨论了深能级杂质缺陷对Ⅲ-Ⅴ族化合物材料与器件的性能的重要影响。介绍了结谱法、光致发光与电子自旋共振等几种研究深中心的方法在研究Ⅲ-Ⅴ族化合物时的某些特点。评述了对砷化镓、磷化镓和磷化铟及某些Ⅲ-Ⅴ族混晶中的一些深中心所取得的研究成果。     

FeSe_(0.4)Te_(0.6)超导薄膜的输运性质实验研究

通过脉冲激光沉积技术制备了超导转变温度约为12 K的FeSe0.4Te0.6超导薄膜,测量了该薄膜晶体结构和在磁场(0-12 T)下的电输运性质。分别用传统的Arrhenius Plots和一种更精确的关系对薄膜的TAFF区的热激活能进行了分析,得到激活能对磁场和温度的指数关系;对两种方法分析结果分析比较,发现第二种方法的分析结果更符合FeSe0.4Te0.6超导薄膜的测量结果。估算了FeSe0.4Te0.6超导薄膜的玻璃态转变温度、上临界场Hc2(0)和相干长度。     

Impact of ZnTe buffer on the electrical properties of n-type GaSb:Te films

We have investigated on the molecular beam epitaxy (MBE) of Te-doped GaSb films on ZnTe buffer. Te-doped GaSb (GaSb:Te) films with and without ZnTe buffer were grown on (0 0 1) GaAs substrates. GaSb:Te/ZnTe/GaAs film revealed higher mobility (=631 cm²/V s) in comparison to GaSb:Te/GaAs film (=249 cm²/V s). To explain the higher mobility of GaSb:Te on ZnTe buffer, dislocation density and temperature dependence of Hall measurement results were analyzed. Temperature dependence of Hall measurement shows strong influence of the dislocation scattering, which indicates that dislocation reduction by the ZnTe buffer enhances the carrier mobility of GaSb films.     

Optical properties of Cd<Subscript>0.6</Subscript>Mn<Subscript>0.4</Subscript>Te/Cd<Subscript>0.5</Subscript>Mg<Subscript>0.5</Subscript>Te quantum-well structures

Emission spectra of three Cd_0.6Mn_0.4Te/Cd_0.5Mg_0.5Te superlattices with Cd_0.6Mn_0.4Te quantum-well (QW) widths of 7, 13, and 26 monolayers, respectively, and the same thickness (46 monolayers) of the Cd_0.5Mg_0.5Te barriers have been studied. The QW width affects the shape and spectral position of the Mn²⁺ intracenter luminescence (IL) band as a result of the crystal field being dependent on the position of the manganese ion with respect to the interface. Measured in identical experimental conditions, the exciton luminescence as compared to the IL is substantially higher in intensity in a QW than in a bulk CdMnTe crystal. Some samples of superlattices and bulk crystals exhibit, in addition to the conventional IL band near 2.0 eV, a weaker band at about 1.45 eV. This band apparently derives from intracenter transitions in the Mn²⁺ ions in the regions where the crystal lattice has the rock-salt rather than the conventional zinc blende structure.