The migration mechanism and the minimum energy path of vacancies, interstitials, and an interstitial-vacancy pair in zinc oxide were studied by the dimer method. The in-plane and out-of-plane migrations of zinc and oxygen vacancies were anisotropic. The kick-out mechanism was energetically preferred to zinc and oxygen interstitials that could easily migrate through the ZnO crystal lattice. In addition, the migration process of an interstitial-vacancy pair as a complex of an octahedral oxygen interstitial and a zinc vacancy was dominated by an oxygen interstitial/zinc vacancy successive migration. The energy barriers indicate that the existence of oxygen interstitial in the defect pair could promote the mobility of zinc vacancy, whereas the migration of oxygen interstitial was slowed down due to the presence of zinc vacancy. Finally, a possible migration path of the interstitial-vacancy pair was shown that could be dissociated via a set of displacement movements.

Migration of Point Defects and a Defect Pair in Zinc Oxide using the Dimer Method. Chen, D., Gao, F., Dong, M., Liu, B.: Journal of Materials Research, 2012, 27[17], 2241-8