First-principles study of p-type conductivity of N-Al/Ga/In co-doped ZnO

N-mono doped and N-Al/Ga/In co-doped ZnO were investigated by first-principles calculations. We have studied the structural and electrical properties, the p-type conductivities and the defects formation energies of different doped structures. The results showed that the Fermi level moved downward into the valance band and showed p-type conductivity after doping. From the hole carriers analysis, it was found that the hole carriers concentration in N-doped ZnO was larger than the others and had a greater hole effective mass, while the co-doping ZnO had a better carriers transfer character, and the (N,Ga)-ZnO structure showed optimal mobility. The defects formation energy of N-ZnO was relatively high; however, the value of the (N-Al)-ZnO structure on both the O-rich and Zn-rich conditions was low, implying a feasible dual-doped approach.