MCT晶体退火压力——温度关系及其分析

采用热重法组分不同（ｘ＝０．１５～０．２５，ｙ＝０．５０～０．５４）的（Ｈｇ１－ｘＣｄｘ）１－ｙＴｅｙ晶体ｓ－ｇ平衡体系进行了Ｐ－Ｔ关系测量（Ｔ〈５６０℃，Ｐ＝２～７６ｋＰａ）；发现ｘ值不同的样品对Ｐ－Ｔ的影响不明显；ｙ值偏离（ｙ≥０．５０４）的样品在４２０±５℃有ＰＨｇ降，并对此进行了分析，提出了利用此现象可以减少ＭＣＴ晶体中的富Ｔｅ量和改善Ｔｅ组分均匀性；补充了５１ｋＰａ以下的Ｐ－Ｔ数据，通过     

用PICTS研究非掺杂半绝缘CdTe的深能级

本文首次报道了采用光激电流瞬态谱（ＰＩＣＴＳ）研究非掺杂半绝缘ＣｄＴｅ的深能级。结果表明，晶体内部的深能级决定着半绝缘材料的电阻率，０．１－０．１９ｅＶ深能级带是决定电阻率高低的重要因素；ＰＩＣＴＳ反映的是晶体内的深能级，与样品（１１１）ＣｄＴｅ的Ａ、Ｂ面和表面光洁度关系不大。     

GaInP材料生长及其性质研究

用Ｘ光双晶衍射、Ｈａｌｌ和光致发光研究了ＭＯＣＶＤ生长的ＧａｘＩｎ１－ｘＰ（ｘ＝０．４７６～０．５０５）外延层．发现Ｇａ组分随Ｖ／Ⅲ比的增大略有下降，认为是由于Ｇａ－Ｐ键比Ｉｎ－Ｐ键强所造成的．７７Ｋ下电子迁移率达３３００ｃｍ２／（Ｖ·ｓ）．Ｇａ０．５Ｉｎ０．５Ｐ的载流子浓度随生长温度升高、Ｖ／Ⅲ比的增大而降低，提出磷（Ｐ）空位（Ｖｐ）是自由载流子的一个重要来源．１７Ｋ下ＰＬ峰能和计算的带隙最大相差１１３ｍｅＶ，这可能与ＧａＩｎＰ中杂质或缺陷以及其中存在有序结构有关．     

用XPS对CdTe（111）面进行化学特性分析

用ＸＰＳ化学位移和定量分析方法，研究了露于室温空气中的ＣｄＴｅ（１１１）面的化学特征。首次报道了经机械抛光表面上形成的表面化合物为ＴｅＯ２（Ｔｅ３ｄ５／２５７５．８ｅＶ，Ｏ１ｓ５３０．１ｅＶ）和Ｃｄ（ＯＨ）２（Ｃｄ３ｄ５／２４０５１ｅＶ．Ｏ１ｓ５３１．４ｅＶ）。并与基体里的ＣｄＴｅ共存；经２％Ｂｒ－乙醇溶液化学抛光，表面上形成的化合物为ＣｄＴｅＯ４（Ｃｄ３ｄ５／２４０５．３ｅＶ，Ｔｅ３ｄ５／２５７６５ｅＶ，Ｏ１ｓ５３１．２ｅＶ）和ＴｅＯｘ（ｘ＜１）（Ｔｅ３ｄ５／２５７４～５７５ｅＶ，Ｏ１ｓ５２８１ｅＶ），并且ＸＰＳ谱中没有基体里的ＣｄＴｅ的特征，其中ＴｅＯＸ为Ｔｅ氧化物的过渡态。结果表明，在相同氧化环境中，表面上形成的化合物强烈依赖表面状况。     

MOCVD生长的未掺杂的In1-xGaxP中的本征缺陷

利用深能级瞬态谱（ Ｄ Ｌ Ｔ Ｓ）和瞬态光电阻率谱（ Ｔ Ｐ Ｒ Ｓ）研究了利用金属有机物化学气相沉淀（ Ｍ Ｏ Ｃ Ｖ Ｄ）方法生长的未有意掺杂的 Ｉｎ１－ ｘ Ｇａｘ Ｐ中缺陷对载流子的俘获和发射过程。利用 Ｄ Ｌ Ｔ Ｓ测量观测到了一个激活能为０３５ ｅ Ｖ 的缺陷,由 Ｔ Ｐ Ｒ Ｓ测量确定该缺陷的俘获势垒值介于１８０ ｍ ｅ Ｖ 到２４０ｍ ｅ Ｖ 之间。该缺陷的俘获势垒值的大的分布解释为缺陷周围原子重组的微观波动。同时在 Ｔ Ｐ Ｒ Ｓ测量中观测到俘获势垒为００６ ｅ Ｖ 和０４０ ｅ Ｖ 的两个缺陷。     

C6M—C38 COMMANDER 6 调制器（3）

（上接第１０期）附录Ａ技术指标Ｃｏｍｍａｎｄｅｒ６调制器技术指标视频标准标准基带输入电平范围０．５～２．０ＶＰ－Ｐ,用于８７．５％调制度编码视频输入电平１．０ＶＰ－Ｐ,额定８７．５％调制度视频输入阻抗７５Ω标称视频输入回传损耗３０ｄＢ最小Ｒ系数２Ｔ脉冲　３％最大Ｓ／Ｎ比率６０ｄＢ最小频率响应±０．７５ｄＢ最大→５．０ＭＨｚ微分增益±０．３５ｄＢ在８７．５％调制度微分相位３％Ｐ－Ｐ最大斜率／线路时间失真１．０％最大　　音频标准输入电平范围－１０～＋１０ｄＢｍ输入阻抗６００Ω平衡频率响应±１．０ｄＢ…     

MOCVD生长的Ⅱ－Ⅵ族化合物固溶体组分的热力学分析2．Hg_（1－x）Cd_xTe体系

本文对ＭＯＣＶＤ生长Ｈｇ１－ｘＣｄｘＴｅ进行了热力学分析．所用的起始原材料为Ｈｇ、ＤＭ－Ｃｄ和Ｒ２Ｔｅ．计算结果一方面表明ＣｄＴｅ优先并入倾向使得在通常的ＤＡＧ工艺中ｘ值非常不易控制．另一方面表明即使在Ｈｇ存在的情况下，也可以沉积几乎纯的ＣｄＴｅ，这对实现ＩＭＰ工艺非常有利，计算结果还表明ＩＩ／ＶＩ比对ＨｇＣｄＴｅ的组分控制起着关键性的作用．在ＤＡＧ工艺中，较低的ＩＩ／ＶＩ比可以改善对ｘ值的控制能力，ＬＭＰ－ＤＡＧ工艺是降低ＩＩ／ＶＩ比的较好途径．本文还计算了生长温度和反应室压力对固相组分的影响以及ＬＭＰ     

低压MOCVD生长n型GaN肖特基势垒的研究

用低压ＭＯＣＶＤ法生长了ｎ型ＧａＮ薄膜，对其肖特基势垒进行了表征和推导。真空度低于１×１０＾－６Ｔｏｒｒ时，用电子束蒸发淀积Ｐｔ或Ｐｄ薄层，形成肖特基接触。ｎ－ＧａＮ薄膜上的Ｐｔ肖特基势垒高度，用电流（应为电容－校者注）－电压压法（Ｃ－Ｖ）和电流密度－温度法（Ｊ－Ｔ）测量分别是１．０４和１、０３ｅＶ。同样地基于Ｃ－Ｖ和Ｊ－Ｔ测量方法，测得的ｎ－ＧａＮ上的Ｐｄ垫垒高度分别为０．９４和０．９１ｅＶ。在     

夹层压电复合材料的研究

使用碳黑／Ｐ（ＶＤＦ－ＴＦＥ）导电复合材料与０－３型ＰＺＴ／Ｐ（ＶＤＦ－ＴＦＥ）压电复合材料进行二次结构复合,形成夹层压电复合材料,对其压电性能进行了分析测试。研究结果表明,夹层压电复合材料的压电系数（ｄ３３、ｄ３１）比原单层０－３型ＰＺＴ／Ｐ（ＶＤＦ－ＴＦＥ）压电复合材料有明显提高。此外,从理论上分析说明了其压电系数提高的原因在于夹层压电复合材料受到外部应力作用时,产生了内部应力。     

用PICTS研究非掺杂半绝缘CdTe的深能级

本文首次报道了采用光激电流瞬态谱（ＰＩＣＴＳ）研究非掺杂半绝缘ＣｄＴｅ的深能级。结果表明，晶体内部的深能级决定着半绝缘材料的电阻率，０．１～０．１９ｅＶ深能级带是决定电阻率高低的重要因素；ＰＩＣＴＳ反映的是晶体内的深能级，与样品（１１１）ＣｄＴｅ的Ａ、Ｂ面和表面光洁度关系不大。     

Microwave Synthesis and Characterization of the Series Co1−x Fe x Sb3 High Temperature Thermoelectric Materials

The use of microwave energy for materials processing has a major potential and real advantages over conventional heating such as (1) time and energy savings, (2) rapid heating rates (volumetric heating vs. conduction), (3) considerably reduced processing time and temperature, (4) fine microstructures and hence improved mechanical properties and better product performance, and (5) finally lower environmental impact. In this study, we investigated the use of microwave-assisted synthesis to synthesize a series of Co_1?x Fe _x Sb₃ using this novel approach, which gave high quality materials with little or no impurities in a fraction of the time needed for conventional synthesis. X-ray diffraction analysis was used to examine the structure and the lattice parameters of the samples, while scanning electron microscopy with energy dispersive x-ray spectroscopy was used to study the morphology of the compounds. The samples were sintered by spark plasma sintering, and the highest ZT of 0.33 was obtained for x = 0.2 at 700 K.     

Structural and Magnetic Study of Cu x FeCr1−x O2 Oxides Under High External Magnetic Fields

The structural, electronic, and magnetic behaviors of Cu _x FeCr_1?x O₂ polycrystals are investigated. Investigations are conducted for increasing chromium substitution, according to varying x values in the formula versus copper, for x = 0, 0.2, 0.4, 0.6, 0.8, and 1. The magnetic response of polycrystalline samples under increasing external magnetic field from 0.4 T to 5 T is also studied. The partial crystal structure deformation/transition from delafossite CuFeO₂ structure to corundum-type FeCrO₃ structure containing CrO₂ and Cr₂O₃ blocks is determined. The change in the crystal structure geometry with increasing Cr substitution is observed. Besides, prominent changes in magnetic ordering are observed from antiferromagnetic (x = 1, 0.8, and 0.6) to ferromagnetic ordering (x = 0.4 and 0.2) for high applied external magnetic fields above 2 T.     

High work function Ir/sub x/Si gates on HfAlON p-MOSFETs

We have fabricated the fully silicided Ir/sub x/Si-gated p-MOSFETs on HfAlON gate dielectric with 1.7-nm equivalent oxide thickness. After 950/spl deg/C rapid thermal annealing, the fully Ir/sub x/Si/HfAlON device has high effective work function of 4.9 eV, high peak hole mobility of 80 cm/sup 2//V/spl middot/s, and the advantage of being process compatible to the current VLSI fabrication line.     

Extrema of sin x/x function

An accurate, closed-form approximation that gives the extrema of the sin x/x function is derived. A simple, rapid recursion formula for exact determination of the extrema is also presented     

Microstructure of GaN1−x Bi x

In this paper we describe detailed transmission electron microscopy studies of GaN_1?x Bi _x with 0.05 < x < 0.18 grown by low-temperature molecular beam epitaxy under Ga-rich conditions. Microstructural transformation from columnar growth separated by thin amorphous areas in the films with lowest Bi content (5%) to pseudo-amorphous structure with crystalline grains embedded in the amorphous matrix in the samples with higher Bi content (13% to 18%) was observed. In addition, metallic Bi segregation occurred in the samples with the highest Bi concentration. An abrupt decrease in absorption edge energy is found in samples with higher Bi content.     

高质量0.6 Kb/s声码器的TMS320VC55x实现

给出了一种编码速率为600b／s的高质量声码器算法及基于DSP芯片的硬件实现。介绍了语音编解码算法原理、声码器系统的硬件结构、工作流程以及软件实现与代码优化。针对C55xDSP芯片的结构特点,采用C与汇编混合编程,汇编指令优化等方法,大大降低了算法的存储复杂度和运算复杂度,达到了实时性要求。     

Molecular beam epitaxy of CdSe and the derivative alloys Zn1−x Cd x Se and Cd1−x M x Se

We report the epitaxial growth of CdSe, Zn_1−x Cd _x Se (0 ≤x ≤ 1) and Cd_1−x Mn _x Se (0 ≤x ≤ 0.8) on (100) GaAs. X-ray diffraction (XRD), electron diffraction and transmission electron microscopy (TEM) indicate that all the epilayers have the cubic (zinc-blende) structure of the GaAs substrate. The energy gaps of these materials were measured using reflectivity measurements. We also report the growth of ZnSe/Zn_1−x Cd _x Se superlattices. TEM and XRD measurements show that high quality modulated structures with sharp interfaces are possible.     

ZnSxTe1—x三元混晶的光学性质研究

报道了对一系列不同组份的ＺｎＳｘＴｅ１－ｘ（０≤ｘ〈１）混晶的喇曼菜射和光致姚研究，室温下的喇曼散实验结果表明ＺｎＳｘＴｅ１－ｘ中的声子具有双模行为，研究了ＺｎＳｘＴｅ１－ｘ混晶的反射谱，背散射和边发射配置下的光致发光谱，以及１０～３００Ｋ温度范围内光至发光谱的温度关系，结果表明：ｘ较小时，ＺｎＳｘＴｅ１－ｘ的发光来源于混晶带边发光或浅杂质的发光，ｘ接近１时，发光蜂来源于束缚在Ｔｅ等电子自陷激子的