电子科技 ›› 2020, Vol. 33 ›› Issue (11): 11-15.doi: 10.16180/j.cnki.issn1007-7820.2020.11.003

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CdZnTe晶体缺陷的交流阻抗谱研究

牟浩1,2,谢经辉2,3,刘雨从2,王丁1,沈悦3,王林军3   

  1. 1.上海理工大学 材料科学与工程学院,上海 200093
    2.中国科学院 上海技术物理研究所,上海 200083
    3.上海大学 材料科学与工程学院,上海 200444
  • 收稿日期:2019-12-09 出版日期:2020-11-15 发布日期:2020-11-27
  • 作者简介:牟浩(1994-),男,硕士研究生。研究方向:半导体物理。|王丁(1982-),男,博士,讲师。研究方向:石墨烯基催化剂及半导体气敏材料。
  • 基金资助:
    国家自然科学基金(11933006);科技部重大研发计划(2016YFB0402405);科技部重大研发计划(2016YFA0202201);科技部重大研发计划(2016YFA0202203);中科院前沿重点项目(QYZDJ-SSW-SLH018)

Investigation on the Crystal Defects of CdZnTe by AC Impedance Spectrum

MU Hao1,2,XIE Jinghui2,3,LIU Yucong2,WANG Ding1,SHEN Yue3,WANG Linjun3   

  1. 1. School of Materials Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
    2. Shanghai Institute of Technical Physics, Chinese Academy of Science, Shanghai 200083, China
    3. School of Materials Science and Engineering, Shanghai University, Shanghai 200444, China
  • Received:2019-12-09 Online:2020-11-15 Published:2020-11-27
  • Supported by:
    National Natural Science Foundation of China(11933006);The Major R&D Plan of Ministry of Science and Technology(2016YFB0402405);The Major R&D Plan of Ministry of Science and Technology(2016YFA0202201);The Major R&D Plan of Ministry of Science and Technology(2016YFA0202203);Key Frontier Project of Chinese Academy of Sciences(QYZDJ-SSW-SLH018)

摘要:

宽禁带II-VI族半导体化合物碲锌镉(CdZnTe)晶体是制备室温X和γ射线探测器的理想半导体材料,但其晶体缺陷特性对探测器性能有重要的影响,一直是人们研究的热点与难点。文中采用垂直布里奇曼法生长了CdZnTe晶锭,XRD测试表明晶片呈现(111)取向。通过测试样品不同温度下的交流阻抗谱,研究了晶体缺陷的阻抗特性。结果表明,制备的CdZnTe单晶具有负温度系数效应,化学法制备的Au电极与晶片之间形成了欧姆接触,没有出现电极界面和晶界对阻抗谱曲线影响,晶粒导电机制占主导。利用Arrhenius方程拟合曲线获得晶体缺陷的激活能为0.48 eV,表明晶体缺陷以Cd空位为主。

关键词: 碲锌镉, 晶体缺陷, 激活能, 交流阻抗谱

Abstract:

Tellurium cadmium zinc (CdZnTe) is a kind of II - VI wide band-gap semiconductor compound, which is a promising material to fabricate the X- or γ-ray detectors. The crystalline defects of CdZnTe has a significant influence on the detector performance, which has been paid more and more attention. In this work, CdZnTe crystalline wafer is grown by vertical Bridgman method, and XRD measurement shows that the wafer is (111) oriented. The impedance characteristics of crystal defects are studied by measuring the AC impedance spectra of the samples at different temperatures. The results show that the prepared CdZnTe single crystal exhibits a negative temperature coefficient effect, and Ohmic contact has been formed between the Au electrode prepared by chemical method and the wafer. The effect of electrode interface and grain boundary is not observed, and the mechanism of grain conduction is dominant. The fitted activation energy of the defect is about 0.48 eV determined by fitting the Arrhenius equation, indicating that Cd vacancy is the main crystal defect.

Key words: CdZnTe, crystal defect, activation energy, AC impedance spectroscopy

中图分类号: 

  • TN304.2