First-principles Study of Electronic and Optical Properties in Wurtzite ZnCoO Alloys

We perform a first-principles simulation to research the electronic and optical properties of wurtzite Zn1-xCoxO. The simulations are based on the Perdew-Burke-Ernzerhof form of generalized gradient approximation within the density functional theory. Calculations are carried out in different concentrations. With increasing Co concentration, the band gap of Zn1-xCoxO decreases due to the shift of valence band. Besides, it is shown that the insertion of Co atom leads to redshift of the optical absorption edge. Meanwhile, the optical constants of pure ZnO and ZnCoO alloys such as loss function, refractive index and reflectivity, are discussed.