Mechanisms for p-type behavior of ZnO, Zn_(1-x)Mg_xO, and related oxide semiconductors

摘要

The possibilities of turning intrinsically n-type oxide semiconductors like ZnO and Zn_(1-x)Mg_xO into p-type materials are investigated. Motivated by recent experiments on Zn_(1-x)Mg_xO doped with nitrogen, we analyze the electronic defect levels of point defects N_O, v_(Zn), and N_O-v_(Zn) pairs in ZnO and Zn_(1-x)Mg_xO by means of self-interaction-corrected density functional theory calculations. We show how the interplay of defects can lead to shallow acceptor defect levels, although the levels of individual point defects N_O are too deep in the band gap to be responsible for p-type conduction. We relate our results to p-type conduction paths at grain boundaries seen in polycrystalline ZnO and develop an understanding of a p-type mechanism which is common to ZnO, Zn_(1-x)Mg_xO, and related materials.