Calculation of electronic and optical properties of the quaternary alloys Zn 1− xCd xS ySe 1− y

Abstract

The electronic and optical properties of the II–VI semiconductors ZnS, ZnSe, CdS, CdSe and their alloys Zn 1− x Cd x S y Se 1− y have been are investigated using the empirical pseudopotential method. For the quaternary alloy ZnCdSSe, we have coupled the virtual crystal approximation with the pseudopotential method. The energies of the Γ, X, and L conduction valleys of the Zn 1− x Cd x S y Se 1− y alloys as a function of y were calculated. The electronic structures of Zn 0.9Cd 0.1S 0.2Se 0.8 and Zn 0.9Cd 0.1S 0.15Se 0.85 alloys were studied for lattice matching to GaAs as well as ZnSe. Also the composition dependence of the refractive index and the dielectric function of II–VI quaternary alloys were also calculated.