PV型探测器对激光辐照的动态响应

本文建立了ＰＶ型光是探测器生载流子输运的动力学模型，该模型公作少量的简化、能适用于任何强度的激光辐照。通过数值坟解其相应的动力学方程，得到了光生电动势的瞬态特性和饱和特性，且与实验结果达到较好的一致。     

1. 319μm 激光诱导HgCdTe (PV 型)探测器混沌的研究

通过对1. 319μm 连续波激光辐照PV 型HgCdTe 探测器的实验研究,发现当激光辐照 功率密度超过探测器的饱和阈值以后,激光能诱导探测器产生混沌现象,并得出了相应的激光辐照功率密度范围,文中还对试验结果进行了论证与分析。     

1. 319μm 激光诱导HgCdTe (PV 型)探测器混沌的研究

通过对1.319μm连续波激光辐照PV型HgCdTe探测器的实验研究，发现当激光辐照功率密度超过探测器的饱和阈值以后，激光能诱导探测器产生混沌现象，并得出相应的激光辐照功率密度范围，文中还对试验结果进行了论证与分析。     

光电探测器激光损伤热模型分析

本文在考虑了激光在材料内的热源效应后,求解了热扩散方程,给出了三种情况下激光破坏阈值与脉宽的关系式。借助材料表面的温度分布曲线,讨论了材料破坏的热机理。用这一模型可预测材料的破坏阈值,验证数值计算的结果;在已知某一脉宽的破坏阈值求另一脉宽下的阈值时也是有效的。最后比较了实验结果与理论预测值,它们在一定范围内符合得很好。     

激光对星载单元探测器的损伤效应分析

给出激光损伤星载单元探测器的技术途径和估算方法，并以InSb探测器材料为例，初步分析波长为1．315μm的激光对空间卫星探测器可能造成的损伤效应。     

Hg1-xCdxTe长波光伏探测器的低频噪声研究

在同一Hg1-xCdxTe晶片上（x=0．217）制备了单层ZnS钝化和双层（CdTe＋ZnS）钝化的两种器件,对器件的低频噪声和暗电流进行了测试．发现单层钝化的器件在反偏较高时具有较高的低频噪声,在对器件的暗电流拟合计算中发现,单层钝化的器件具有较大的表面隧道电流,而这正是单层钝化器件具有较高低频噪声的原因．并通过高分辨X射线衍射中的倒易点阵技术RSM（reciprocal space mapping）研究了两种钝化对HgCdTe外延层晶格完整性的影响,发现单层ZnS钝化的HgCdTe外延层产生了大量缺陷,而这些缺陷正是单层钝化器件具有较高的低频噪声和表面隧道电流的原因．     

激光辐照对红外探测器的损伤

根据红外探测器的结构特点和传热学理论,研究激光干扰机的激光器对探测器的损伤效果。以InSb探测器为例,设定入射激光从顶层辐照,结合各层之间热传导效应建立分层热模型。考虑激光在空间上的分布为高斯分布,给定初值和边界条件,利用Matlab偏微分工具箱进行建模仿真。重点研究了辐照距离、辐照时间和激光器功率等因素对探测器损伤效果的影响,给出了相应的仿真结果。当连续激光功率为50 W、距离为200 m、辐照时间为3 s时,对探测器的损伤效果主要是软损伤,受激光功率密度所限,未能造成永久性破坏。     

CW CO2激光对PV型InSb探测器的破坏效应

通过测量光伏型锑化铟探测器在不同功率密度、不同辐照时间的CW CO2激光辐照时性能的变化,得到其破坏阈值区间.理论上用一维热模型计算了探测器在激光辐照过程中的温升,结果表明,PV型InSb探测器的破坏效应源于连续波激光辐照过程中温升达到InSb材料熔点时其pn结退化为电阻.     

激光对光电探测器的损伤阈值研究

本文研究了1.06μm和0.53μm激光对硅pin光电二极管以及硅雪崩光电管的永久性损伤效应,测出了损伤阈值。实验发现,光电探测器的PN结受到激光热烧伤是造成其永久性损伤的重要因素,损伤阈值的大小与激光波长、脉冲宽度以及光电探测器结构有关。     

强激光对光电探测器的损伤机理研究

详细讨论了强激光对光电探测器的损伤类型，并初步讨论了损伤机理。提出了一种测定光电探测器损伤的实验方法。     

Single crystal growth of Hg1-xCdxTe

It has been found that single crystals of Hg_1-xCd_xTe with volumes of about 3 cm³ can be obtained using a new method for crystal growth. Experimental details of the new technique as applied to Hg_1-xCd_xTe are discussed. Single crystal growth mechanisms are proposed which involve crystallization from a two-phase mixture followed by recrystallization of the solid. Evidence for the unusually high quality material is obtained from electron-beam microprobe analyses, electrical properties, and magneto-optical spectra. This work was sponsored by the Department of the Air Force.     

激光辐照光伏型锑化铟探测器的损伤机制研究

本文研究激光辐照光伏型梯化铟探测器的损伤机制，指出激光的损伤使局部ｐｎ结退化为电阻，对器件性能的影响等效于并联一个电阻，用来解释实验中的各种现象，理论与实验曲线符合得很好。该模型也可以解释闪光效应，即光照对此种器件的修复作用。     

Hgl-xCdxTe的拉曼光谱

我们发观Hg1-xCdxTe的拉曼散射峰随着温度的变化会发生频移,它的二级散射峰来自L01+LO1,LOl+LO2,L02+LO2,并且它们的强度对晶体的完整性较敏感.同时也发现Hgl-xCdxTe中的Te的沉淀相和Te的氧化物相的拉曼散射峰.     

非晶态碲镉汞的光学性质

采用椭圆偏振光谱技术研究了射频磁控溅射生长非晶态碲镉汞(amorphous Hg1-xCdxTe,amorphous MCT,a-MCT)薄膜的光学性质,发现非晶态碲镉汞薄膜的介电函数谱特征与晶态碲镉汞材料的明显不同,表现出与其他非晶态半导体材料类似的“波包”结构特征.基于修正的FB模型在1.0～4.0 eV的能量范围内对实验结果进行了拟合分析,得到了不同组分非晶态碲镉汞薄膜的光学带隙随组分关系.通过与单晶碲镉汞光学带隙随组分变化关系的对比研究,结果表明碲镉汞的结构从晶态向非晶态转变过程中,材料的光学待续发生了明显的“蓝移”.     

碲镉汞体材料的显微Raman光谱

利用Raman显微镜测量了ACRT-Bridgman方法和Te溶剂方法生长的碲镉汞体材料的显微Raman光谱,在碲镉汞体材料的显微Raman光谱中识别出了碲镉汞的基本光学振动模,由此证明了碲镉汞按品格振动的分类方法属于二模混晶;识别出了一个来源于类HgTe的TO1模+LO1模的二级Raman散射峰;观察到了碲镉汞体材料中两个新的Raman散射峰,分别位于662 cm-1和749 cm-1;观察到了碲镉汞基本光学振动模的TO1模与LO1模的Raman散射强度比的变化,指出该现象是由于Raman散射几何配置不同引起的.     

Molecular beam epitaxy of CdTe and Hg1-xCdxTe ON GaAs (100)

Using the molecular beam epitaxial (MBE) technique, CdTe and Hg_1-xCd_xTe have been grown on Cr-doped GaAs (100) sub-strates. A single effusion cell charged with polycrystal-line CdTe is used for the growth of CdTe films. The CdTe films grown at 200 °C with a growth rate of ~ 2 μm/hr show both streaked and “Kikuchi” patterns, indicating single crystalline CdTe films are smoothly grown on the GaAs sub-strates. A sharp emission peak is observed at near band-edge (7865 Å, 1.577 eV) in the photoluminescence spectrum at 77 K. For the growth of Hg_1-xCd_xTe films, separate sources of HgTe, Cd and Te are used. Hg_0.6Cd_0.4Te films are grown at 50 °C with a growth rate of 1.7 μm/hr. The surfaces are mirror-smooth and the interfaces between the films and the substrates are very flat and smooth. As-grown Hg_0.6Cd_0.4Te films are p-type and converted into n-type by annealing in Hg pressure. Carrier concentration and Hall mobility of an annealed Hg_0.6Cd_0.4Te film are 1 × 10¹⁷ cm^?3 and 1000 cm²/V-sec at 77 K, respectively.     

Minimally cooled heterojunction laser heterodyne detectors in metalorganic vapor phase epitaxially grown Hg1-xCdxTe

By taking advantage of Auger suppression techniques, the leakage currents of room temperature infrared detectors operating in the LWIR band can be greatly reduced. At present, these detectors suffer from large 1/f noise and hence the improvement in the detectivity resulting from the reduced leakage currents can only be realized at high frequencies. However, this is not a problem for heterodyne systems which employ intermediate frequencies above 40 MHz. A thermo-electrically cooled Auger suppressed infrared detector operated at 260K has been studied as a heterodyne detector. The device was operated with the application of sufficient local oscillator power to double its dark current (about 0.3 mW) and a NEP of 2 x 10^-19 W Hz⁻¹ was deduced from heterodyne measurements. The frequency response is presently limited by a combination of the detector capacitance and the series resistance to about 70 MHz and ways to reduce this series resistance are considered.     

Hg1-xCdx Te晶体生长及太赫兹性能研究

利用移动加热区方法(THM)生长了不同Cd组分的Hg1-xCdxTe晶体,通过傅立叶光谱仪和太赫兹时域光谱系统,研究了不同Cd组分Hg1-xCdxTe晶体在红外波段和太赫兹波段的透射光谱.当Cd组分小于0.279时,Hg1-xCdxTe材料在0.2～1.5 THz波段透过率接近0.在0.9 THz附近观察到Hg1-xC...     

Process modeling of point defect effects in Hg1-xCdxTe

A model is presented which describes the motion of and interactions among some of the native point defects and foreign impurities in Hg_1-xCd_xTe. Semi-quantitative simulations of typical process problems are performed for cases where only Hg interstitials, Hg vacancies, and cation impurities are important. Results for the formation of n-on-p junctions by the Hg anneal of high vacancy concentration material, indicate that junction depths may be a significant function of the n-type dopant concentration. For the case where low vacancy, n-type material is annealed in a Hg-poor ambient, simulation results confirm the difficulty in forming a high quality, well-defined p-on-n junction. This difficulty arises because of the generation of Hg vacancy/interstitial pairs throughout the bulk during most of the process. It is demonstrated that impurity gettering can be described by our modeling approach. All simulation results attempted to date are consistent with the available experimental data.     

Compositional dependence of infrared phonon parameters for Hg1-xCdxTe

The full set of Lorentzian oscillator parameters describing the two-mode phonon behavior in Hg_1-x-jCd_xTe is reported. A new analysis of reflectivity spectra combined with existing results gives the most accurate available values for the CdTe-like and HgTe-like transverse optical frequency, strength and (for the first time) damping constant vs CdTe fractionx at room, liquid nitrogen and liquid helium temperatures. Polynomial fits vsx for each parameter are provided for use in characterizing Hg_1-xCd_xTe and the HgTe-CdTe superlattice.