The Delocalized Nature of Holes in (Ga, N) Cluster-Doped ZnO

A spin-polarized density-functional theory study is presented here, revealing that a single hole state created by (Ga, N) cluster doping in ZnO contains the contributions from all of the N atoms in the cluster. This is in contrast to the situation where N atoms alone are doped into ZnO, and have a highly localized hole state centered around the dopant N atoms. Hence, this study shows that an enhanced delocalized hole state can be obtained if an appropriate electronic environment is provided.