The Effects of Dual Acceptor (Na, N) Doping on Zn and O Sites in ZnO

ZnO is an attracted semiconducting material because of the intriguing structural, electronic and optical properties as well as the properties can easily be tuned for applications. However, p-type doping is an essential research interest to overcome the hindering of the applications of n-type ZnO for next-generation advanced electronic and optoelectronic devices. In this article, we focus on the p-type acceptor mono (Na, N) and dual (Na-N) doping effects on the structural, electronic and optical properties of ZnO using first-principles calculations based on the density functional theory (DFT). Detailed DFT analysis reveals that the structure of ZnO distorted resulting in (Na, N) and (Na-N) doping, respectively. Band structure calculation highlights the confirmation of p-type ZnO for both types of doping introduced by acceptor impurity bands at the top of the valence band and pushing the Fermi level into the valence band. The band gap of ZnO is increased for Na and Na-N doping, while decreases for N doping.  The widening of the band gap with Na and Na-N doping could be explained by Burstein Moss effect. In this study the band gap can be tuned in between 0.58 and 0.93 eV. Importantly, enhancement of the absorption and photoconductivity in the near band edge region attributed to (Na, N) and (Na-N) could be extended its applications in high-performance p-type based electronic and optoelectronic devices.