Electronic structures and optical properties of Ⅲ_A-doped wurtzite Mg_0.25Zn_0.75O

The energy band structures, density of states, and optical properties of Ⅲ_A-doped wurtzite Mg_0.25Zn_0.75O (Ⅲ_A=Al, Ga, In) are investigated by a first-principles method based on the density functional theory. The calculated results show that the optical bandgaps of Mg_0.25Zn_0.75O:Ⅲ_A are larger than those of Mg_0.25Zn_0.75O because of the Burstein-Moss effect and the bandgap renormalization effect. The electron effective mass values of Mg_0.25Zn_0.75O:Ⅲ_A are heavier than those of Mg_0.25Zn_0.75O, which is in agreement with the previous experimental result. The formation energies of MgZnO:Al and MgZnO:Ga are smaller than that of MgZnO:In, while their optical bandgaps are larger, so MgZnO:Al and MgZnO:Ga are suitable to be fabricated and used as transparent conductive oxide films in the ultra-violet (UV) and deep UV optoelectronic devices.