In-N共掺杂ZnO第一性原理计算

First principles study of In-N codoped ZnO

采用基于密度泛函理论(DFT)的第一性原理平面波超软赝势方法计算了纤锌矿ZnO,N掺杂和In-N共掺杂ZnO晶体的电子结构,分析了N掺杂和In-N共掺杂ZnO晶体的能带结构、电子态密度、差分电荷分布以及H原子对In-N共掺杂ZnO的影响.计算结果表明:N掺杂ZnO在能隙中引入了深受主能级,载流子(空穴)局域于价带顶附近.而加入激活施主In的In-N共掺杂ZnO,受主能级向低能方向移动,形成了浅受主能级.同时,受主能级带变宽、非局域化特征明显、提高了掺杂浓度和系统的稳定性.文章的结论与实验结果相符,从而为实验上,In的掺入有助于实现ZnO的p型掺杂提供了理论支持.文中还指出H原子的存在会大大降低掺杂效率,对p型掺杂产生不利影响,应该在反应中尽量避免.

The electronic structure of pure N-doped and In-N codoped wurtzite ZnO has been calculated by using first-principles ultra- soft pseudo-potential approach of the plane wave based upon the density functional theory, and the structure change, bandstructure,density of states, difference charge density and the influence of ln-N codoped wurtzite ZnO by H atom were studied. The calculation results revealed that N-doped wurtzite ZnO caused formation of deep N acceptor levels in the band gap and the carriers （hole） were localized near the top of the valence band. But the codoping calculation revealed that the acceptor level shifted toward the lower-energy region and shallow acceptor level were fomed, which was broadened and showed delocalizing characters, owing to which the concentration of impurities and the stability of the system were enhanced. Our conclusions accord with the results of experiments, which confirms the fact that In-N codoping in wurtzite ZnO helps the formation of p-type ZnO. In addition, it was also pointed out that the presence of H atom reduces the efficiency of doping markelly, which should be avoided as much as possible.