Au在Hg_(1-x)Cd_xTe材料中p型掺杂的第一性原理研究

利用基于密度泛函理论的第一性原理方法,研究了Au在Hg1-xCdxTe材料中原位取代Hg的p型掺杂对材料各组分电子结构的影响.通过态密度、形成能和动力学能级的理论分析,系统讨论了分子外延(MBE)和液相外延(LPE)两种生长条件下,Au杂质p型掺杂的稳定性和有效性.结果表明Au原位取代Hg后,Hg1-xCdxTe材料一方面表现出相当好的稳定性,另一方面形成浅杂质能级,是一种有效的p型掺杂剂.讨论了生长气氛对Au在Hg1-xCdxTe(MCT)中p型掺杂效率的影响,发现在MBE生长条件下,富阳离子气氛的所有组分,富Te气氛的0.75x≤1组分以及LPE生长富阳离子条件下的0.75≤x≤1组分的MCT材料中均存在Au杂质的自补偿效应,不适合进行Au的p型掺杂.

First-principles study of gold p-type doping in Hg_(1-x) Cd_x Te

Using plane-wave pseudopotential methods based on the density functional theory, we have studied the structural and the electronic properties of gold doped Hg_(1-x)Cd Te (MCT).The results indicate that the in situ gold impurity maintains stabile bonds with the host atoms.Moreover, the in situ gold impurity creates a shallow aeceptor level behaving as an efficient p-type dopant.For all mole fractions under molecular beam epitaxy (MBE) cation-rich growth condition, for 0.75 < x≤ 1 under MBE Te-rich growth condition, and for 0.75 ≤ x ≤ 1 under liquid phase epitaxy cation rich growth condition, the self-compensating effect occurs and the gold impurity cannot behave as an efficient p-type dopant in MCT.