Indentation-introduced dislocation rosettes and their effects on the carrier transport properties of CdZnTe crystal
Indentation-introduced dislocation rosettes and their effects on the carrier transport properties of CdZnTe crystal
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压痕引入的位错花结及其对 CdZnTe 晶体载流子传输性能的影响
DOI：
10.1039/c6ce00519e
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发表时间：
2016
期刊：
影响因子：
3.1
通讯作者：
Jie Wanqi
中科院分区：
文献类型：
--
作者：
Fu Xu;Xu Yadong;Xu Lingyan;Gu Yaxu;Jia Ningbo;Bai Wei;Zha Gangqiang;Wang Tao;Jie Wanqi
本文研究了CdZnTe（CZT）晶体中压痕引入的玫瑰花状位错团的晶体学结构及其对载流子输运过程的影响。采用维氏硬度试验在室温下在CZT晶体的Te面人工产生位错。由Everson蚀刻剂显示的蚀刻坑密度（EPD）显示，位错密度从4.9 × 104 cm-2增加到太高的浓度，以至于在压痕后无法评估。提出了一个解释玫瑰花状位错团的模型。结果表明，这种尺寸小、EPD高的四面体属于Te面的Te（g）位错。压痕过程中形成的堆积物的六边形分布是由CZT的锌层结构决定的，而不是压头的方向。根据Lomer和Cottrell提出的位错塞积规律，对位错塞积现象进行了观察和分析。离子束感生电荷（IBIC）测量显示位错产生区域中的低载流子收集效率（CCE），这证实位错和相关缺陷可以显著降低CZT探测器的CCE。低温光致发光（PL）的测量结果表明，位于1.485 eV的发射峰高度增加的压痕区域，是负责的性能下降的探测器。
Herein, we study the crystallographic configuration of rosette-like dislocation clusters introduced by indentation in CdZnTe (CZT) crystal and the effects of the dislocations on the carrier transport process. The Vickers hardness test was used to generate dislocations artificially on the () Te face of the CZT crystal at room temperature. Etch pit density (EPD) revealed by Everson etchant showed that the dislocation density increased from 4.9 × 104 cm−2 to a concentration too high to be evaluated after the indentation. A model was proposed to explain the rosette-like dislocation clusters. It was verified that the tetrahedron with small size and high EPD belonged to Te(g) dislocations on the () Te face. The hexagon-like distribution of pile-ups formed during the indentation was determined by the zinc-blende structure of CZT, rather than the direction of the indenter. The dislocation pile-up during propagation was observed and analyzed based on the rule proposed by Lomer and Cottrell. The ion beam induced charge (IBIC) measurements showed low carrier collection efficiency (CCE) in the dislocation generation areas, which confirms that the dislocations and related defects can significantly degrade the CCE of a CZT detector. Measurements of low temperature photo-luminescence (PL) showed that the emission peak located at 1.485 eV highly increased in the indentation area and was responsible for the performance degradation of the detectors.