Ab initio methods were used to predict the diffusion coefficient of As dopants in ZnO as a function of Fermi level. Contributions to As diffusion from interstitial, simple substitutional, and cluster diffusion were considered. Formation and migration energies for Zn vacancies (VZn), As substituting on Zn lattice sites (AsZn), complexes of As with up to two Zn vacancies (AsZn-1VZn and AsZn-2VZn), and interstitial Zn and As (ZnI,oct and AsI,oct) were calculated using GGA + U and hybrid Hartree-Fock density-functional theory calculations. AsZn was the dominant As-containing donor and AsZn-2VZn was the dominant As-containing acceptor. At low Fermi levels, As was mostly immobile, while at high Fermi levels, AsZn-2VZn was mobile with a migration energy of 1.6 eV.

Atomistic Modeling of As Diffusion in ZnO. B.Puchala, D.Morgan: Physical Review B, 2012, 85[6], 064106