STRUCTURAL AND OPTICAL STUDIES ON VACUUM-EVAPORATED ZNSEXCDS1-X ALLOY-FILMS

(ZnSe)(x)(CdS)(1-x) films (about 6 mu m thick) in the entire range of x have been formed on glass substrates kept at 470 K by thermal evapor ation. All the films exhibited n-type conductivity. X-ray diffraction (XRD) studies showed that films with 0 less than or equal to x less th an or equal to 0.70 were polycrystalline with the wurtzite phase, wher eas films with 0.8 less than or equal to x less than or equal to 1.0 c rystallized in the zincblende phase. The lattice parameter varied line arly with x following Vegard's law in both the structures. The direct optical band gaps varied non-linearly, showing a downward bowing with increasing x. The bowing parameter was found to be about 0.39 eV. The structural transformation region of x obtained by analysing band gap d ata was found to agree well with that obtained from XRD studies.