碲镉汞阳极硫化膜界面的光电子能谱研究

用电子能谱方法研究了Hg_(1-x)Cd_xTe样品在0.1M的Na_2S·9H_2O+乙二醇溶液中形成的阳极硫化膜,结果表明界面上汞的含量较高,介质膜含氧;但在0.1M的Na_2S·9H_2O+NaOH+乙二醇溶液中形成的阳极硫化膜几乎不含氧,介质膜的主要成分是CdS,且含有较多的Hg和Te。结果表明,碲镉汞表面的含水硫化可以获得同无水硫化、无水多硫化和含水多硫化钝化表面基本一致的介质膜,从而实现了含水硫化钝化碲镉汞表面。     

中波碲镉汞边缘接触不对称MIS结构的低频噪声

对两种不同结构的中波碲镉汞光导红外探测器件的噪声进行了测量,发现叠层结构器件的低频噪声比具有简单结构器件的大。针对叠层结构,提出了用来分析噪声的边缘接触不对称MIS结构模型。分析表明,叠层电极下的碲镉汞表面在偏置电压作用下,容易出现耗尽层是低频噪声增加的主要原因。     

碲镉汞材料及工艺控制的分析方法

随着碲镉汞红外器件的小型化、高品质化和性能的提高,对原材料的纯度、器件工艺质量控制方法提出了更高的要求。就分析方法而言,不仅要求有高的定量分析精度,同时要求分析方法对杂质元素的分析范围广(多元素分析)、元素的探测灵敏度高。对器件工艺控制分析来说,除了基体元素成分、杂质元素的定量分析外,还要求分析方法能在横向和纵向分析,并有相当的空间分辨率。就上述要求给出了碲镉汞材料提纯、CMT(碲镉汞,Cd(?)Hg(?)Te)晶体生长及器件工艺控制分析的主要分析技术方法、特点及其进展。讨论了基体元素定量分析的精度,痕量元素定量分析的能力、灵敏度及其进行深度剖面分析的深度分辨率。     

室温辐射探测器用碲锌镉晶体的退火改性研究进展

碲锌镉(CdZnTe)作为一种重要的Ⅱ-VI族化合物半导体,因其具备优异的光电性能,成为制备室温辐射探测器的理想材料.但生长态的CdZnTe晶体中不可避免地会引入Cd空位、沉淀/夹杂相、杂质和位错等缺陷,严重影响了所制备器件的质量和光电性能.因此,需对生长态晶体进行退火改性处理以提高晶体的质量.本文分析了CdZnTe材...     

长波红外对常温目标的跟踪成像研究

靶场观测中存在大量不发光和表面温度接近常温的低温目标,根据它们的光谱辐射特性、背景辐射特性和大气透过率与目标距离的关系,分别选择了中波和长波红外探测器对降落伞进行气球放飞试验。试验结果表明,长波红外探测器对常温目标的探测要优于中波红外。选择分辨力320×256 的碲镉汞探测器作探测能力实验,以 SNR≥5 为可探测条件,当目标表面温度大于 260K时,对直径 5m 的降落伞的作用距离可达 50Km。     

CdZnTe晶体热处理诱生的层错研究

首次对碲锌镉晶体热处理诱生层错的微观结构及形成机理进行了研究.碲锌镉晶体的层错能较高,形成困难,但在热处理过程中富Te相从晶体中心热迁移至表面时在晶内产生了应力,使晶体的晶格处于受拉状态,从而过饱和Te原子插入,导致局部区域原子密排面的层序发生错排,形成稳定的堆垛层错.层错的腐蚀金相蚀坑由一条条倾斜富Te槽构成,这些倾斜富Te槽沿(111)密排面排列成为一条条相互交成60°、120°的直线,其交线方向为[110]晶向.     

一种全新的金属有机配合物非线性光学晶体CdHg(SCN)_4(C_2H_5NO)_2的生长、物化和光学性能表征

在以水和N-甲基甲酰胺的混合溶剂中制备了一种潜在的二阶非线性光学晶体:二N-甲基甲酰胺合硫氰酸汞镉(CdHg(SCN)4(C2H5NO)2(CMTN));用溶液降温法生长出了尺寸为30 mm×27 mm×9mm的较高光学质量的单晶体。采用元素分析、粉末衍射、红外和拉曼光谱、热分析和紫外/可见/近红外透过光谱表征了它的结构、物理化学、热分解和光学性质。该晶体在128.5℃开始分解,其紫外截止波长为358nm。     

Hg1-xCdxSe红外薄膜材料研究进展

硒镉汞(Hg_(1-x)Cd_xSe)作为碲镉汞(Hg_(1-x)Cd_xTe)的红外替代材料受到广泛关注,它具有位错密度低、热膨胀系数小、晶格失配小等优势,可望获得高质量、大面积、廉价长波红外(Long-wavelength infrared,LWIR)焦平面阵列(Focal plane arrays,FPAs)。综述了Hg_(1-x)Cd_xSe材料的最新研究进展,讨论了Hg_(1-x)Cd_xSe薄膜材料在不同衬底和不同生长条件下对薄膜质量的影响及最新研究结果;同时,对Hg_(1-x)Cd_xSe材料的研究进行了展望。     

拓扑绝缘体HgTe纳米材料制备技术

概述了近期碲化汞纳米材料的各种制备技术的研究进展,并总结了制备、技术中出现的问题。结合晶体生长机理,分析了碲化汞量子点、纳米线等典型的形貌特征。介绍了碲化汞制备技术研究中具有代表性的几个课题组的研究动向。结合本课题组的研究进展,讨论了碲化汞制备过程中碲源和汞源所存在的问题。最后展望了碲化汞的制备技术改进。     

激光能量对碲镉汞注入样品退火效果的影响

利用脉冲ＹＡＧ激光器对砷注入长波碲镉汞样品进行激光退火、分析不同能量密度的激光光束退火所引起的样品表面电学性质的变化。实验表明,激光能量密度越大,激光退火的效果越明显。我们认为要达到理想退火效果,样品表面一薄层需处迂近熔化状态,以得到晶格结构的重新组织。     

HgCdTe晶体ACRT-B法生长过程的分凝特性研究

在定量估算的基础上，明确了Ｈｇ１－ｘＣｄｘＴｅ晶体ＡＣ－ＲＴ－Ｂ法生长过程轴向溶质再分配的 经条件，导出了计算公式。以ＨｇＴｅ－ＣｄＴｅ伪二元相图为基础进行了计算表明，按照远红外控制器要求的成分配料（ｘ０＝０．２２），仅在晶锭的某一部分可获得符合成分容差的晶体，而采用其它相近的成分配比也能获得符合成分要求的晶体，采用ｘ０值更小的槽糕成分获得的满足成分要求的晶段更长，并且位于结晶质量较高的晶锭前段‘     

Hg1-xCdxTe材料AES定量分析中的电子束和离子束效应

在Hg1-xCdxTe材料的AES分析中 ,由于分析电子束辐照作用 ,可诱导表面Hg原子的脱附和热升华 ,导致短时间内样品表面严重失Hg ,使AES定量分析结果产生很大的误差。实验结果表明 ,在超高真空中分析电子束辐照下局部Hg元素的挥发损失以负指数关系进行。通过选择离子束溅射速率大于电子束蒸发速率 ,并在溅射的同时进行俄歇信号收集 ,则可减小或消除分析电子束对元素Hg的蒸发作用 ,获得稳定的俄歇信号。实验结果还指出 ,溅射离子束的参数会影响元素的相对溅射产额 ,具体定量分析时应选择相同的溅射条件     

Effects of mercaptopropionic acid as a stabilizing agent and Cd:Te ion ratio on CdTe and CdHgTe quantum dots properties

In the present work, mercaptopropionic acid (MPA) capped CdTe and CdHgTe quantum dots (QDs) are synthesized using a method based on the bottom up approach in aqueous medium. The CdTe QDs were prepared with a two different ratios of Cd:Te (3:1 and 4:1). It was noticed that there was a minimum concentration of MPA for each Cd:Te ratio. The resulting QDs were characterized using optical absorption spectroscopy, energy dispersion X-ray (EDX) and high resolution transmission electron microscopy (HRTEM). It was found that the EDXs of CdTe and CdHgTe QDs showed that the stiochiometric ratios of CdTe obtained with Cd:Te ratio of 3:1 is 50:50 and for CdHgTe is 40:26:34 for 100?% of Hg. The band gap of CdHgTe QDs varies slightly with composition from 2.21?eV for a pure CdTe to 1.4?eV for a CdHgTe with 100?% of Hg. The HRTEM image showed a good dispersed nano-crystalline structure for the CdTe QDs with average size of 3–4?nm. The existence of the lattice planes on the HRTEM images of the QD indicated that the CdTe QDs are highly crystalline. In addition, the CdHgTe QDs size is 12?nm for 100?% of Hg.     

Cd0.8Mn0.2Te晶体的磁化强度和法拉第效应研究

采用垂直Bridgroan法制备出了x=0.2的Cd1-xMnxTe晶体(Cd0.8Mn0.2 Te).利用MPMS-7(magnetic property measurement system)型超导量子磁强计测量了Cd0.8Mn0.2Te晶体的磁化强度(M)与磁场强度(H)和温度(T)的关系,磁场强度范围为-159...     

Some peculiarities of (Hg,Cd) Te liquid-phase epitaxial growth in a semi-closed,two-zone system

A semi-closed, two-zone system for (Hg, Cd) Te liquid-phase epitaxy (LPE) is described which has the main advantage of closed systems: namely, there is no loss of mercury from the solution. The system retains all the good properties of open systems, i.e. it simplifies the repeated use. One other advantage is the possibility of rinsing the system in pure hydrogen. In order to establish the experimental conditions for obtaining the LPE (Hg, Cd) Te layers of desired composition on the CdTe or CdZnTe substrates, it is first necessary to study the problems of maintenance of the already homogenized solution composition, homogenization rate, and the epitaxial layers' composition changes as a function of solution supercooling.     

Hg1—xCdxTe液相外延薄膜的晶体质量分析

本文用Ｘ－射线双晶遥摆曲线，分析了Ｈｇ１－ｘＣｄｘＴｅ外延薄膜的晶体质量。结果表明，用垂直浸渍液相外延方法生长的Ｈｇ１－ｘＣｄｘＴｅ薄膜，结构均匀性好，晶体质量高，Ｈｇ１－ｘＣｄｘＴｅ外延薄膜表面层的晶体质量，优于其界面层；同时，Ｈｇ１－ｘＣｄｘＴｅ外延薄膜表面层的位错密度，可通过Ｘ－射线双晶遥摆曲线的半峰算得到。     

Detector-grade CdZnTe:In crystals obtained by annealing

A method for successfully obtaining detector-grade CdZnTe:In (CZT:In) crystals by annealing is described in this article. Pure Te is used as annealing source, which can provide sufficient deep-level Te antisites. Characterizations reveal that the resistivity is greatly enhanced by more than five orders after this annealing, thus the crystals can be use for radiation detectors. This is due to introduce efficient Te antisites to pin the Fermi level to the middle of the band gap. The EPD of dislocation reduces because the star-like Cd inclusions are eliminated by annealing. Investigation of annealing time shows that 240 h annealed CZT:In crystal with 7.8% energy resolution and 2.01×10⁻³ cm²/V μτ value has the best detector performance.     

P型高阻CdZnTe晶体表面接触的电学性能研究

用原子力显微镜（ＡＦＭ）研究了Ｐ型高阻Ｃｄ０．８Ｚｎ０．２Ｔｅ晶体表面状况对接触电学特性的影响,研究了三种金属和ＡｕＣｌ３作为接触层材料的电学特性和接触机理。研究表明采用化学方法沉积ＡｕＣｌ３膜能在ＣｄＺｎＴｅ光滑表面形成一层重掺杂层,较金属更易获得欧姆接触,热处理可改善接触的欧姆性,增强接触层与晶体表面的结合力。     

Electro- and Heat Transfer in $$\mathbf{Cd}_{\mathbf{0.22}}\mathbf{\hbox {Hg}}_{\mathbf{0.78}}{} \mathbf{Te}$$ Single Crystals in the Temperature Range of Their Practical Applications

The thermal and electrical conductivity of a single-crystal \(\hbox {Cd}_{0.22}\hbox {Hg}_{0.78}\hbox {Te}\) was studied in the temperature range of practical applications (77–300 K). The sample has impurity conductivity, which is limited by the scattering of charge carriers by phonons. Heat in the sample is transferred by phonons and thermal conductivity is limited by phonon–phonon scattering. The electron contribution to the thermal conductivity can be neglected.     

Synthesis and characterization of cysteamine-CdTe quantum dots via one-step aqueous method

A novel approach has been developed to synthesize cysteamine (CA)-CdTe quantum dots (QDs) in an aqueous medium. Compared with previous reports, the proposed method involves a one-step synthesis using TeO₂ to replace Te or Al₂Te₃ as tellurium source. The influences of the precursor Cd/Te molar ratios and the pH of the original solution on the quantum yield (QY) of the obtained CdTe QDs were investigated systematically. Green- to orange-emitting CdTe QDs, with a maximum photoluminescence QY of 10.73%, were obtained. X-ray powder diffraction and transmission electron microscopy were used to characterize the crystalline structure and shape of the materials. CdTe QDs with CA modification exhibit a zinc-blended crystal structure in a sphere-like shape.