ZnO能带及态密度的密度泛函理论研究

Density Functional Theory Study on Energy Band and Density of States of ZnO

本文采用基于密度泛函理论框架下第一性原理的平面波赝势方法,并采用局域密度近似(LDA)理论和ABINIT软件对ZnO电子结构进行了计算。得到了ZnO的能带和态密度曲线。研究表明,ZnO的价带基本上可以分为三个区域,即下价带区、上价带区和位于-18.1eV处的宽度为1.1eV的价带;导带部分主要是由Zn的4s态贡献的,O的2p态在该区域内具有微弱的贡献;ZnO是一种直接宽禁带半导体,导带底和价带顶位于布里渊区中心处,带隙为0.9eV,相对比较该结果优于一些文献给出的计算值。

The electrical structure of ZnO is calculated by first principles pseudo-potential approach of the plane wave based upon the density functional theory （DFT） using local density approximation （LDA） and ABINIT package. The curves of energy band and density of states （DOS） of ZnO are gained. After analyzing it＇s known that the valence band can be basically divided into three regions, i.e. lower valence band, upper valence band and the one located in - 18. 1 eV with the width of 1.1 eV; the part of conduction band is mainly contributed by 4s state of Zn, and 2p state of O has only a little contribution in this area. ZnO is a kind of semiconductor material with a direct and wide energy band. The bottom of conduction band and the top of valence band are both in point G in the centre of Brillouin zone. The energy gap is 0.9 eV, which is better than some of the computed results given by some literatures.