Cd1-xZnxTe晶体中由本征缺陷引起的导电类型转变界面研究

Position-Dependent Conductivity Transition by Intrinsic Defects in Cd1-xZnxTe Crystal

  • 摘要: 在富Te生长条件下,采用垂直布里奇曼法(vertical Bridgman method, VB)生长的部分碲锌镉(Cd1-xZnxTe, CZT)晶体内存在导电类型转变界面。为深入探讨碲锌镉晶体导电类型转变界面形成的原因,结合晶体导电类型和红外光谱透过率的测试结果与第一性原理的理论计算进行分析,结果表明,碲锌镉晶体内的导电类型转变界面是晶体生长过程中形成的Cd空位(VCd)缺陷与Cd间隙(Cdi)缺陷导致的。在富Te条件的生长过程中,Cd空位缺陷易于形成,碲锌镉晶体材料中含有大量的Cd空位缺陷,材料的导电型为p型。在晶体生长结束阶段的降温过程中,Cd原子会扩散至碲锌镉晶体中,促进了Cd间隙缺陷的形成,在碲锌镉晶体材料中形成Cd间隙缺陷,导致晶体材料的导电性转变为n型。

     

    Abstract: In this study, the formation of a position-dependent conductivity transition in Cd1-xZnxTe crystals is investigated. The results indicate that the transition from p- to n-type Cd1-xZnxTe (x = 0.04) can be ascribed to the formation of the VCd-Cdi interface. Cd vacancies (VCd) are easily generated in the Te-rich condition crystal growth process and are responsible for the p-type conductivity. However, Cd vacancies are filled and the n-type defect, Cd interstitial (Cdi), form in the Cd-rich condition. This leads to the transition from p-type to n-type conductivity during the growth of Cd1-xZnxTe (x = 0.04).

     

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