First principles calculations of structural, electronic and optical properties of Sn-doped ZnS

Using the full potential linearized augmented plane wave approach within the density functional theory (DFT), the structural, electronic and optical properties of Zn1-XSnXS (X = 6.25, 12.5 and 25%) solid solutions in most stable cubic phase of ZnS are computed. The bandgap values are calculated by using Tran-Blaha approach of modified Becke and Johnson (TB-mBJ) local spin density approximation. For Sn-doped ZnS, the compounds are non-magnetic indirect bandgap semiconductors with narrow bandgaps. The contribution of the Sn-5p state near Fermi level in the valance band reduces the bandgap of the doped systems. Optical characteristics are estimated using the dielectric function spectra as well as other associated optical properties such as absorption coefficient, reflectivity, refractive index, extinction coefficient and conductivity. The investigation shows that this compounds might be a good choice for optoelectronic devices.