Based on ab initio total energy calculations, the diffusion mechanisms of group-III elements (B, Al, Ga, and In) in ZnO were investigated. The activation energy of vacancy-assisted mechanism consists of formation energy of Zn vacancy (VZn), binding energy between the dopants and VZn, as well as effective diffusion energy barrier of the dopants in ZnO. The effective diffusion energy barriers of B, Al, Ga, and In were estimated to be 1.12, 1.76, 1.45 and 1.06eV for in-plane diffusion, and 1.12, 2.19, 1.80, and 1.06eV for out-of-plane diffusion, respectively. The binding energies were estimated to be −0.66, −0.52, −0.48 and −0.43eV for B-, Al-, Ga-, and In-VZn pairs, showing a size decreasing behaviour.

Vacancy-Assisted Diffusion Mechanism of Group-III Elements in ZnO: an Ab Initio Study. G.Y.Huang, C.Y.Wang, J.T.Wang: Journal of Applied Physics, 2009, 105[7], 073504