Mechanisms for p-type behavior of ZnO, Zn1-xMgxO, and related oxide semiconductors

摘要

The possibilities of turning intrinsically n-type oxide semiconductors like ZnO and Zn1-xMgxO into p-type materials are investigated. Motivated by recent experiments on Zn1-xMgxO doped with nitrogen, we analyze the electronic defect levels of point defects NO, vZn, and NO-vZn pairs in ZnO and Zn1-xMgxO 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 NO 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, Zn1-xMgxO, and related materials.