First-principle investigation of K–N dual-acceptor codoping for p-ZnO

A novel dual-acceptor strategy was proposed for obtaining p type ZnO by codoping nitrogen (N) with potassium (K). Based on density functional theory within the local density approximation, a first-principle investigation has been performed on the electronic structure and main defects of K–N codoped wurtzite ZnO crystal. After doping K and N simultaneously, an acceptor shallow level appeared above valence band maximum approximate 0.24 eV, which was lower than that of monodoping K or N. It indicated that K–N dual acceptor codoping will be a benefit for obtaining more stable p type conductivity ZnO than mono-doping does. Additionally, such point defects as Zn vacancy in (K–N): ZnO system acted as a deep acceptor (0.41 eV) and was not a main source for hole carriers; H interstitial, however, behaved as an unfavorable donor to compensate acceptor level.