摘要
The performance of CdZnTe X/γ-ray detectors is strongly affected by the electric field distribution in terms of charge transport and charge collection. Factors which determine the electric field distribution are not only electric contact, but also intrinsic defects, especially grown-in twin boundaries. Here, the electric field distribution around twin boundaries is investigated in a CdZnTe bicrystal detector with a {111}–{111} twin plane using the Pockels electro-optic effect. The results of laser beam induced current pulses are also obtained by the transient current technique, and we discuss the influence of the twin boundary on the electric field evolution. These studies reveal a significant distortion of the electric field, which is attributed to the buildup of space charges at twin boundaries. Also, the position of these space charge regions depends on the polarity of the detector bias. An energy band model based on the formation of an n–n＋–n junction across the twin boundary has been established to explain the observed results.
The performance of CdZnTe X/γ-ray detectors is strongly affected by the electric field distribution in terms of charge transport and charge collection. Factors which determine the electric field distribution are not only electric contact, but also intrinsic defects, especially grown-in twin boundaries. Here, the electric field distribution around twin boundaries is investigated in a CdZnTe bicrystal detector with a {111}–{111} twin plane using the Pockels electro-optic effect. The results of laser beam induced current pulses are also obtained by the transient current technique, and we discuss the influence of the twin boundary on the electric field evolution. These studies reveal a significant distortion of the electric field, which is attributed to the buildup of space charges at twin boundaries. Also, the position of these space charge regions depends on the polarity of the detector bias. An energy band model based on the formation of an n–n＋–n junction across the twin boundary has been established to explain the observed results.
作者
董江鹏
介万奇
余竞一
郭榕榕
Christian Teichert
Kevin-P Gradwohl
张滨滨
罗翔祥
席守智
徐亚东
Jiangpeng Dong1,2, Wanqi Jie1,2, Jingyi Yu2, Rongrong Guo3, Christian Teichert4, Kevin-P Gradwohl4, Bin-Bin Zhang2, Xiangxiang Luo2, Shouzhi Xi2, and Yadong Xu1,2(1 State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi＇an 710072, China 2 Key Laboratory of Radiation Detection Materials and Devices, Northwestern Polytechnical University, Xi＇an 710072, China 3 School of Optoeletronic and Communication Engineering, Xiamen University of Technology, Xiamen 361024, China 4Institute of Physics, Montanuniversitaet Leoben, Leoben 8700, Austri)
基金
Project supported by the National Natural Science Foundation of China(Grant Nos.U1631116 and 51702271)
the National Key Research and Development Program of China(Grant No.2016YFE0115200)
the Natural Science Basic Research Plan in Shaanxi Province of China(Grant No.2017KW-029)
Austrian Academic Exchange Service(D-WTZ)through project CN 02/2016
the Fundamental Research Funds for the Central Universities of China(Grant Nos.3102017zy057 and 3102018jcc036)
the Young and Middle-aged Teachers Education and Scientific Research Foundation of Fujian Province,China(Grant No.JAT170407)
