采用多步骤组合退火方法改善碲镁镉晶体的性能  

Enhanced Properties of CdMgTe Crystals by Multi-Step Annealing Method

作　　者：张嘉伟 俞鹏飞 韩召 杨桂芝 介万奇[2] ZHANG Jiawei;YU Pengfei;HAN Zhao;YANG Guizhi;JIE Wanqi(School of Materials Science and Engineering,Chang'an University,Xi'an 710064,China;State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi'an 710072,China)

机构地区：[1]长安大学材料科学与工程学院,西安710064 [2]西北工业大学,凝固技术国家重点实验室,西安710072

出　　处：《硅酸盐学报》2025年第1期102-113,共12页Journal of The Chinese Ceramic Society

基　　金：西北工业大学凝固技术国家重点实验室开放课题(SKLSP202318);陕西省重点研发计划项目(2022GY-358)。

摘　　要：碲镁镉(CdMgTe)晶体是一种理想的室温辐射探测新材料,但生长态晶体中仍然存在较多的缺陷,降低了探测器性能。采用多步骤组合退火方法对CdMgTe晶体进行退火改性,探讨了退火温度对晶体缺陷、力学、光学和电学性能的影响。结果表明,Cd气氛退火后晶体中的Te夹杂相大幅减少,红外透过率和电阻率明显下降,经Te气氛退火后Te夹杂相密度无明显变化,而红外透过率和电阻率则显著提高且优于生长态晶体。退火后,晶体表面未出现额外氧化,禁带宽度最大增加了0.021 eV,显微硬度最多提高了16%,Raman光谱测试表明晶体中出现了新缺陷,探测器性能出现了质的变化。最佳退火条件获得的CdMgTe晶体制作的平面探测器性能最好,电子迁移率达526.86 cm^(2)/(V·s),能量分辨率和电子迁移率寿命积分别为15.6%和1.89×10^(–4)cm^(2)/V。Introduction Cadmium magnesium telluride(CdMgTe)crystal is an ideal material for room-temperature radiation detection.However,there are still many defects in as-grown crystals,which degrade the detector performance.At present,a single annealing method is unable to achieve the effect of both eliminating defects and maintaining or increasing resistivity.The multi-step combined annealing method can improve the crystal quality and the detector performance.There are a few studies on the annealing of CdMgTe crystals.In this work,a multi-step combined annealing method was used,i.e.,the CdMgTe crystals grown under Te-rich condition were annealed in Cd atmosphere and Te atmosphere.The effect of annealing temperature on the defects,mechanics,photoelectric properties and detector performance of CdMgTe crystals was investigated.Methods High purity(7N)cadmium(Cd)and tellurium(Te)were selected as raw materials.The selected slices for annealing were derived from In-doped Cd_(0.95)Mg_(0.05)Te ingot grown by a modified vertical Bridgman method under Te rich condition,with the size of5 mm×5 mm×2 mm.The annealing in Cd atmosphere was mainly divided into two steps,i.e.,high and low temperature annealing.In the high temperature annealing step,the temperatures of the slices were 873,923 K and 973 K,respectively.The corresponding temperatures of Cd source were 901,946 K and 986 K,respectively.The annealing time was 120 h.After high temperature annealing,the temperature of the slices and Cd source reduced to 623 K,and the annealing time was also 120 h.After annealing in Cd atmosphere,it continued annealing in Te atmosphere.The annealing temperature of both slices and Te source was selected to 773 K,and the annealing time was also 120 h.The Cd Mg Te crystals before and after annealing were characterized by infrared transmission microscopy,scanning electron microscopy,ultraviolet-visible-near infrared(NIR)spectroscopy,infrared transmittance spectroscopy,Raman spectroscopy,X-ray photoelectron spectroscopy(XPS),Vickers indentation analysi

关 键 词：碲镁镉晶体 多步骤组合退火 晶体质量 电阻率 室温辐射探测器 

分 类 号：TN304.2[电子电信—物理电子学]