半导体Si和GaAs的GW近似能带结构与BSE吸收光谱的研究

Electronic Structure and Optical Absorption of Si and GaAs by GW Aproximation and BSE Calculation

基于密度泛函理论,采用平面缀加波的广义密度近似的PBE泛函和准粒子近似的GW方法对典型的半导体硅Si和砷化镓GaAs的能带结构进行了研究;同时研究了Si和GaAs的光吸收谱,并利用多体微扰理论的BetheSalpeter方程(BSE)进行了修正。计算结果表明,准粒子近似的GW方法对Si和GaAs的能隙预测结果和实验值符合较好,考虑了电子—空穴对激子效应的GW-BSE多体微扰方法计算的Si和GaAs的介电函数吸收谱与实验谱符合最佳;研究说明激子效应在半导体光谱性质分析方面十分重要。

Based on the density function theory（DFT）,the band structures of semiconductors Si and GaAs were calculated by the Perdew-Burke-Ernzerhof（PBE）function and corrected by the GW method of quasi-particle approximation,using the full-potential projected augmented wave（PAW）method.Then,the optical absorptions of Si and GaAs were presented by DFT and corrected by the BetheSalpeter equation（BSE）of many-body perturbation theory. The calculations indicate that the band gaps obtained by the GW method conform to the experimental values better than DFT results,and the electron-hole interaction significantly affects the optical absorption of Si and GaAs. The BSE results show that the excitonic effect is important in the research on the optical absorption of semiconductor.