Study on the doping stability and electronic structure of wurtzite Zn1−xCdxO alloys by first-principle calculations

Abstract An ab initio calculation based on density functional theory is applied to study the doping stability and electronic structure of wurtzite Zn 1− x Cd x O alloys. It is found that the different alloy configurations of Zn 1− x Cd x O with a given Cd content are possible thermodynamically, but having different band gaps. With increasing Cd content, the formation enthalpy of Zn 1− x Cd x O alloy increases sharply. The Cd-content dependence of the band-gap values can be fitted with a second-order polynomial. The reduction of band gap can be attributed to the contributions of the hybridization of Zn-4 s and Cd-5 s , the enhancement of p–d repulsion, and the tensile strain due to Cd-doping.