The effect of zinc concentration upon optical and dielectric properties of Cd_(1x)Zn_xSe

摘要

Theoretical investigations of the optical and dielectric properties of Cd_(1x)Zn_xSe with zinc-blende crystal structure are reported. The calculations are mainly based on the pseudopotential framework within the virtual crystal approximation in which the effect of compositional disorder is involved. A meaningful agreement with the experimental optical band-gap bowing parameter is only obtained when the disorder effect is included in the calculation. The zinc concentration dependence of the selected features of Cd_(1x)Zn_xSe, such as energy band-gaps, refractive index and dielectric constants has been examined. All studied quantities are found to vary monotonically with zinc concentration x. The high-frequency and static dielectric constants have been scaled with the fundamental band-gap energy (E_g). Such scaling showed that the variation of the dielectric constants versus E_g exhibits a non-linear behavior.