共查询到20条相似文献,搜索用时 10 毫秒
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R. Gul A. Bolotnikov H. K. Kim R. Rodriguez K. Keeter Z. Li G. Gu R. B. James 《Journal of Electronic Materials》2011,40(3):274-279
We studied, by current deep-level transient spectroscopy (I-DLTS), point defects in CdZnTe detectors grown by different techniques. We identified 12 different traps with energy levels from 7 meV to 1.1 eV. Although the levels of most of the identified defects were independent of the crystal growth techniques, nevertheless there were some associated differences in the traps’ energies and densities. 相似文献
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宽禁带II-VI族半导体化合物碲锌镉(CdZnTe)晶体是制备室温X和γ射线探测器的理想半导体材料,但其晶体缺陷特性对探测器性能有重要的影响,一直是人们研究的热点与难点。文中采用垂直布里奇曼法生长了CdZnTe晶锭,XRD测试表明晶片呈现(111)取向。通过测试样品不同温度下的交流阻抗谱,研究了晶体缺陷的阻抗特性。结果表明,制备的CdZnTe单晶具有负温度系数效应,化学法制备的Au电极与晶片之间形成了欧姆接触,没有出现电极界面和晶界对阻抗谱曲线影响,晶粒导电机制占主导。利用Arrhenius方程拟合曲线获得晶体缺陷的激活能为0.48 eV,表明晶体缺陷以Cd空位为主。 相似文献
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Martine C. Duff Douglas B. Hunter Patterson Nuessle David R. Black Harold Burdette Joseph Woicik Arnold Burger Michael Groza 《Journal of Electronic Materials》2007,36(8):1092-1097
Synthetic CdZnTe (CZT) crystals can be used for the room temperature-based detection of gamma radiation. Structural/morphological
heterogeneities within CZT, such as secondary phases (namely, precipitates and inclusions), can negatively affect detector
performance. We used a synchrotron-based x-ray technique, specifically extended x-ray absorption fine-structure (EXAFS) spectroscopy,
to determine whether there are differences on a local structural level between intact CZT of high and low radiation detector
performance. These studies were complemented by data on radiation detector performance and transmission infrared (IR) imaging.
The EXAFS studies revealed no detectable local structural differences between the two types of CZT materials. 相似文献
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M. Pavesi L. Marchini M. Zha A. Zappettini M. Zanichelli M. Manfredi 《Journal of Electronic Materials》2011,40(10):2043-2050
It is well known that group III elements act as donors if they play a substitutional role at the metallic site in II-tellurides; nevertheless, several studies report both on the creation of complexes with vacancies, named A-centers, and on the involvement in self-compensation mechanisms, especially for indium. The boron concentration in II-tellurides is negligible, and its contribution to transport mechanisms has not been studied yet. For the last few years the authors have been developing a new technique to grow CdZnTe by the vertical Bridgman technique, taking advantage of encapsulation by means of boron oxide. In this way, crystals characterized by large single grains, low etch pit density, and high resistivity have been obtained. Recently, x-ray detectors with state-of-the-art performance have been produced from such crystals. Boron contamination, as a consequence of this growth method, is quite low but at least one order of magnitude above values obtained with other growth techniques. Besides being a low-cost technique which is also suitable for large-scale mass production, the encapsulated vertical Bridgman technique is quite useful to prevent dislocations, grain boundaries, and stacking faults; for these reasons, careful characterization was performed to understand the effect of boron both on the electrical properties and on the spectroscopic performance of the final crystals. Our characterization is mainly based on low-temperature photoluminescence in addition to electrical current–voltage measurements, photostimulated current, and x-ray spectroscopy. The results indicate that boron behaves like other group III elements; in fact, boron forms a complex that does not affect the good performance of our x-ray detectors, even if it shows some properties which are typical of A-centers. 相似文献
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Fengfeng Sheng Jianrong Yang Shiwen Sun Changhe Zhou Huixian Yu 《Journal of Electronic Materials》2014,43(7):2702-2708
The influence of Cd-rich annealing at temperatures of 440–900 °C on the defect properties of Te-rich CdZnTe materials was studied. Cd-rich annealing at temperatures above the melting point of Te was confirmed to effectively reduce the size of Te-rich inclusions in the materials. However, dislocation multiplication occurred in the regions near Te-rich inclusions. Etch pit clusters were observed on the surfaces of annealed materials etched with Everson etchant. The etch pit clusters were much larger than the as-grown Te-rich inclusions. The dependence of the cluster size on that of the Te-rich inclusions and the annealing conditions was investigated. The density of etch pits in the normal region increased when the annealing temperature exceeded 750 °C. The mechanisms of the evolution of the Te-rich inclusions and the formation of new defects during the Cd-rich annealing are discussed. 相似文献
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M. Reddy W. A. Radford D. D. Lofgreen K. R. Olsson J. M. Peterson S. M. Johnson 《Journal of Electronic Materials》2014,43(8):2991-2997
HgCdTe dual-band epitaxial layers on lattice-matched CdZnTe substrates often have morphological defects. These defects, unlike normal void and microvoid defects, do not contain a polycrystalline core and, therefore, do not offer a good contrast for observation using optical and electron microscopes. This paper reports a way of identifying these defects by using a Nomarski optical microscopy image overlay on focused ion beam microscopy images for preparation of thin cross-sectional foils of these defects. Transmission electron microscopy was used to study the defect cross-sections to identify the origin and evolution of the morphological defects and their effect on the epitaxial layer. This paper reports cross-sectional analysis of four morphological defects of different shape and size. 相似文献
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P. Moravec Z. F. Tomashik V. G. Ivanits’ka V. M. Tomashik J. Franc K. Ma?ek P. H?schl 《Journal of Electronic Materials》2012,41(10):2838-2845
We report on new etching solutions for treatment of CdTe and CdZnTe surfaces based on the iodine-emerging etchant composition KIO3–KI–citric acid (C6H8O7). CdTe samples with (111), (110), and (100) orientations, and also Cd1?x Zn x Te (x?=?0.04, 0.1) samples with (111), (110), (100), and (211) orientations were investigated. The dissolution rate was determined as a function of solution composition, etchant storage time, disc rotation speed, and temperature. It was established that this chemical dissolution is diffusion controlled. Study of the chemical composition and structure of (211)B Cd1?x Zn x Te surfaces etched under different conditions was carried out. x-Ray photoelectron spectroscopy measurements showed that a stoichiometric surface was achieved after briefly heating the etched surface in a vacuum. Reflection high-energy electron diffraction measurements revealed a high-quality single-crystalline surface layer in samples etched with KIO3–KI–citric acid solutions as compared with those etched with a bromine–methanol treatment. The etching compositions were shown to be useful for controlled removal of semiconductor material, and also for chemical polishing of CdTe-based surfaces. 相似文献
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对青海湖盐晶体进行了结构缺陷的观察和红外透射率的测量,将所得结果与人工生长的氯化纳晶体进行了比较,发现青海湖盐的位错分布和人工晶体的位错分布不同:前者具有单个位错均匀分布的特征,后者除单个位错外,还呈现由位错密排形成的亚晶界网络。两种晶体的红外透射率几乎完全相同,表明天然湖盐晶体的位错密度和分布状况不太影响其红外透射率。 相似文献
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本文介绍一种检测绝缘薄膜缺陷的简易而有效的方法——液晶测量法,并针对交流薄膜电致发光(ACTFEL)器件中常用的几种绝缘薄膜作检测与分析。 相似文献
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采用传输矩阵的方法研究带缺陷的一维光子晶体,纳米缺陷的引入使得原来不透电磁
波的禁带中,出现了缺陷模,即某一频率的电磁波可以透过,计算表明缺陷模的频率与透射谱随着不同介电常量、不同几何结构以及掺杂的晶体结构而改变。 相似文献
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The effect of a fast neutron flux (Φ = 1014–1015 cm–2) on the electrical and photoluminescence properties of p-CdZnTe single crystals is studied. Isothermal annealing is performed (T = 400–500 K), and the activation energy of the dissociation of radiation-induced defects is determined at ED ≈ 0.75 eV. 相似文献
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Superlarge defects in CZ Si : B single crystals were visualized by scanning laser mid-IR microscopy. Previously, these defects were revealed in similar single crystals with the use of an SEM operating in the electron-beam-induced current (EBIC) mode and by small-angle scattering of mid-IR radiation. 相似文献