Optical properties of silicon doped ZnO

We have calculated the optical structure of wurtzite ZnO doped with Silicon (Si). The calculations are based on the density functional theory with the generalized gradient approximation (GGA) and the projector augmented wave pseudopotentials. The GGA with the Perdew Burke Ernzerhof exchange-correlation functional are employed in the simulations. Ultrasoft pseudopotentials are utilized for the geometry optimization to render the computations tractable as well as to enhance the efficiency. We investigate two kinds of defects in ZnO, namely the substitution of Zn by Si and O by Si. The optical properties, including dielectric function, reflectivity and absorption coefficient of wurtzite ZnO are calculated. The variation in the band gap and energetics have been validated against published results. The dielectric properties follow a steep decreasing trend for the low energy level. In addition, the reflectivity and absorption coefficients reduce abruptly due to the doping.