探测器级CdZnTe晶体变温特性研究  

Study on the temperature dependent properties of detector-grade CdZnTe crystals

作　　者：徐亚东[1] 何亦辉[1] 王涛[1] 查钢强[1] 傅莉[1] 介万奇[1] 

机构地区：[1]西北工业大学,凝固技术国家重点实验室,陕西西安710072

出　　处：《功能材料》2011年第3期441-443,447,共4页Journal of Functional Materials

基　　金：国家自然科学基金资助项目(50872111,50902114);教育部“新世纪人才支持计划”资助项目(NCET-07-0689)

摘　　要：采用未经准直能量为5.48MeV的241 Amα粒子,研究了温度在230～300K范围内,不同电场作用下CdZnTe晶体的脉冲响应信号,分析了载流子传输特性随温度变化的规律。对比了室温(298K)以及280K下探测器对241 Am@59.5keVγ射线的响应光谱。同时分析了1500V/cm电场作用下探测器漏电流随温度的变化规律。研究表明,对于性能优异的CdZnTe晶体,载流子迁移率寿命积随温度变化较小。而对于存在de-trapping(去俘获)缺陷的CdZnTe样品,光生载流子在晶体中的传输会显著减缓,且随温度的降低,其对脉冲波形的影响加剧。而温度降低可以减少提高探测器的能量分辨率。To evaluate the charge transport behaviors associated with the temperature variation,the pulse height spectra of CdZnTe crystals were obtained under various bias voltages,in the temperature range of 230-300K,using an un-collimated 241Am α particles source with the energy of 5.48MeV.It was demonstrated that the photo-peak positions were non-sensitive to the temperature for high quality CdZnTe crystals.In terms of CdZnTe crystal with de-trapping level defects,the charge drift velocity was significantly delayed due to the re-emission of charge carriers out of the traps.The pulse shapes shown distinct exponential decay component which enhanced as decreasing the temperature.241Am@59.5keV γ-ray spectroscopy response of CZT detector were compared at room temperature and 280K.In addition,the leakage current of the detector,under the electrical field strength of 1500V/cm,were evaluated as a function of the temperature.

关 键 词：CDZNTE Α粒子 脉冲响应光谱 载流子传输 漏电流 

分 类 号：TN304[电子电信—物理电子学]