Electronic Science and Technology ›› 2020, Vol. 33 ›› Issue (11): 11-15.doi: 10.16180/j.cnki.issn1007-7820.2020.11.003

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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)


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

CLC Number: 

  • TN304.2