【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。更多还原

【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.更多还原