Investigation of structural and electronic properties of native point defects and Ag doping in ZnO applying first principles calculations

In this work, we have investigated the structural and electronic properties of native point defects as well as Ag doping in ZnO applying first principles calculations based on density functional theory. The effect of point defects such as VO and VZn are studied in the increasing and decreasing of p-type carriers. In addition, structural properties, formation energies, defect levels of VO, VZn, Agi, AgO and AgZn are calculated to show the possibility of achieving p-type doping in different environment. VO and VZn are calculated to be donor and acceptor defects, with defect levels of 0.16 eV and 0.20 eV under the conduction band and above the valance band, respectively. At O-rich condition, Ag could replace Zn sites in ZnO crystal structure, which induces an acceptor level 0.14 eV above the top of valance band. As a results, Ag dopant may leads to p-type ZnO in O-rich condition with a proper acceptor level.