First‐Principles Study of the Al–N‐Codoped Zincblende ZnO

Electronic properties of intrinsic ZnO, N‐doped ZnO, and Al–N‐codoped ZnO of both hexagonal wurtzite (HW) and zincblende (ZB) structures are investigated by first‐principles calculations. Both N‐doped ZB‐ZnO and N‐doped HW‐ZnO achieve p‐type transition by the introduction of N‐2p states, forming shallow acceptor levels above the valence band. However, the positive impurity formation energy implies the difficulty and instability of N‐doped ZnO. In Al–N‐codoped ZnO, the Al elements compensate the p‐type doping effect, but partially enhance the solubility of N. Furthermore, the comparison of the electronic properties between HW‐ZnO and ZB‐ZnO indicates that the ZB structure favors the achieving of p‐type doping. Theoretical calculation reveals that N‐doped ZnO achieves p‐type transition by the introduction of N‐2p states, forming shallow acceptor levels above the valence band. In Al–N‐codoped ZnO, the Al compensates the p‐type doping effect, but partially enhances the solubility of N. The comparison between hexagonal wurtzite‐ZnO and zincblende (ZB)‐ZnO indicates that the ZB structure favors the achieving of p‐type doping.