First-principles study of zinc oxide: The p-type doping perspective

The first-principles study with pseudopotentials method based on density functional theory was performed to investigate the native point defects specially oxygen and zinc vacancy of pure ZnO. Also Ag-doped ZnO was studied to determine the ability of p-type conductivity. This investigation was carried out under oxygen-rich (O-rich) and zinc-rich (Zn-rich) conditions. The results indicate that oxygen and zinc vacancies are shallow donors and deep acceptors, respectively. The formation energies show that the oxygen vacancy can easily occur under Zn-rich condition. This would lead to the compensation of p-type doping. We also show that the substitutional Ag atom on the Zn lattice site could be considered as a p-type doping candidate.