Impact of Mg doping contents on the n-type and p-type ZnO by first-principles calculations

The effect of Mg doping on the electrical properties of pure ZnO and Al-doped ZnO, Al-2N co-doped ZnO have been investigated. It was found that after Mg doping, the bandgap values increased with the increase of Mg doping concentration. After Mg was doped into the Al doped ZnO structure, it was found that as the Mg doping contents increased, the CBM gradually moved toward the higher energy direction, the VBM gradually moved toward the lower energy direction, resulting in an increase of the band gap. After Mg was doped into the Al-2N co-doped structure, the band structure of Al-2N-Mg co-doped ZnO had a shallow acceptor level, indicating that the incorporation of Mg is beneficial for the electrical properties of p-type ZnO. The absorption of Al-2N-Mg co-doped ZnO is higher than that of Al-2N co-doped ZnO in the range of the visible region, which has a significant meaning for the applications on solar cell devices.