应变层半导体超晶格价带边不连续性的第一原理研究

THEORETICAL STUDIES ON THE VALENCE-BAND OFFSETS AT STRAINED SEMICONDUCTOR SUPERLATTICES

对处于不同应变状态下的超晶格（ＧａＰ）＿１（ＧａＡｓ）＿１（００１），（ＩｎＰ）＿ｎ（ＩｎＡｓ）＿ｎ（００１）（ｎ＝１，３）的电子结构进行了从头自洽计算。采用冻结势方法分析了超晶格各分子层的价带顶Ｅ＿ｖ和平均键能Ｅ＿ｍ的行为，对以Ｅ＿ｍ为能量参考的应变层超晶格价带边不连续值计算方法作了较全面的第一原理的数值检验，基于这一方法，本文分别对ＩｎＰ，ＩｎＡｓ，ＧａＰ，ＧａＡｓ和Ａｌ－Ａｓ５种化合物在３种不同的应变状态下的Ｅ＿ｍ－Ｅ＿ｖ值作了从头计算，求出了由这几种材料构成的５种应变层超晶格的ΔＥ＿ｖ值，并讨论了它们的应变效应。本文的计算结果与目前可以得到的实验结果及几个有关的界面自洽计算结果相当一致。

Ab initio calculations of electronic structure for strained superlattices(SLS)(GaP)_1(GaAs)_1(001)and(InP)_n(InAs)_n(001)(n=1,3)are carried out,the valence-band maximum E_v and the average bond energy E in each molecular layer of SLS’sare investigated with the frozen shape approach.The average-bond-energy methodfor determining valence-band offsets at SLS’s are suggestted and tested comprehensi-vely.Based on this method,the valence-band offsets at five SLS’s under three st-rain conditions are determined,their strain-induced effects are discussed.The resuIts of present work show good consistency with available experimental data.