Interaction of a zinc interstitial (Zni) with an oxygen vacancy (VO) was investigated to understand an origin of natively n-type characteristics of ZnO using density functional theory with the hybrid functional. The VO–Zni complex was formed with a formation of 3.82eV and was a shallow donor with +1 charge state near the conduction band minimum. Its formation energy, however, was not low enough to be stable thermodynamically. Energy barrier for Zni migration in the VO–Zni complex was studied to consider its existence from kinetic aspect, and a high value of 1.3eV was obtained with the kick-out process. Therefore, the bound Zni to VO can exist and supply electrons for native n-type ZnO kinetically.

Interaction of Zinc Interstitial with Oxygen Vacancy in Zinc Oxide: an Origin of n-Type Doping. D.H.Kim, G.W.Lee, Y.C.Kim: Solid State Communications, 2012, 152[18], 1711–4