采用第一性原理的平面波超软赝势方法,计算了纤锌矿ZnO及不同量Cd掺杂ZnO的电子结构.计算结果表明,Cd的掺杂导致ZnO晶体的禁带宽度变窄.主要原因在于Cd的掺入导致Zn4s轨道中能级越来越低的电子参与作用,使得决定导带底的反键Zn4s态能级逐渐降低,同时由pd反键轨道控制的价带顶能级逐渐升高. The first-principle plane wave ultra-soft pseudopotential method was used to calculate the electronic structure of wurtzite ZnO and different amounts of Cd-doped ZnO. The calculated results show that the doping of Cd leads to narrowing of the bandgap of ZnO crystal. The doping of Cd leads to the electronic participation of Zn4s orbital in the lower and lower energy levels, which leads to the declination of the energy level of the antibonding Zn4s at the bottom of the conduction band and the gradual rise of the valence band energy level controlled by the pd antibonding orbital high.