Positron annihilation lifetime spectroscopy was used to examine grown-in defects in Cd_1–xZn_xTe mixed crystals as a function of Zn content (x = 0, 0.07, 0.11, 0.49, 0.9, 0.95, 1) and measuring temperature. All samples were prepared using the high-pressure modified vertical Bridgman–Stockbarger method. The crystal structure and material phase were characterized by X-ray diffraction. The positron lifetime spectra reveal the presence of both open volumes and shallow traps regardless of the sample composition. In particular, both average and bulk lifetimes are found to be much higher in ternary alloys (CdZnTe) than those in binary systems (CdTe and ZnTe). This originates from distinct differences in average electron densities and the nature of open-volume defects between binary and ternary samples. Competition in positron trapping with increasing Zn content is observed between defects characteristic for both structural systems. Moreover, a clear correlation is shown between defects and the lattice thermal conductivity of studied samples. The applicability of the positron trapping model to CdTe-based materials is discussed.

中文翻译：

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通过垂直 Bridgman-Stockbarger 方法生长的 Cd1-xZnxTe 混合晶体中缺陷结构的正电子寿命光谱

正电子湮没寿命光谱用于检查 Cd _{1– x} Zn _x Te 混晶中的生长缺陷作为 Zn 含量 ( x= 0, 0.07, 0.11, 0.49, 0.9, 0.95, 1) 和测量温度。所有样品均使用高压改进的垂直 Bridgman-Stockbarger 方法制备。通过X射线衍射表征晶体结构和材料相。无论样品成分如何，正电子寿命光谱都显示了开放体积和浅陷阱的存在。特别是，发现三元合金 (CdZnTe) 的平均寿命和体寿命都比二元系统 (CdTe 和 ZnTe) 中的要高得多。这源于二元和三元样品之间平均电子密度的明显差异和开放体积缺陷的性质。在两种结构系统的缺陷特征之间观察到随着 Zn 含量的增加，正电子捕获的竞争。而且，缺陷与所研究样品的晶格热导率之间显示出明显的相关性。讨论了正电子俘获模型对 CdTe 基材料的适用性。