First-principle calculation of electronic structure of the wurtzite CdxZn1-xO

The electronic structures of pure and Cd-doped wurtzite ZnO have been investigated by using first-principle ultrasoft pseudopotential approach of the plane wave. The calculation indicates that the band gap of ZnO is reduced by Cd doping. With increasing Cd-doping concentration, the lower energy states of Zn 4s orbital can take part in hybridization, so that the conduction band of minimum determined by the antibonding Zn 4s states can shift to the lower energy, and the energy of antibonding pd states which control the valence band of maximum becomes higher.