Micro-crystallographic and spectral response studies of CdSe 1 -x Te x alloyed thin films

Chemical deposition of Cdse 1 - x Te x solid solution thin films from salt solutions of cadmium, selenium and tellurium derivatives of sodium sulphite at 70 °C temperature has been presented. The quantitative analyses (EDSand spectrophotometric) showed that the film deposits are Cd rich and compared to the Te, Se content is larger. The variation of x f i l m with x b a t h is non-linear. The XRD studies show composites to be crystalline in nature and both CdSe and CdTe existed in both hexgonal wurtzite and cubic zinc blende structures whereas CdSe 1 - x Te x alloys were hexgonal dominating. Both wurtzite (0 < x < 0.08) and zinc blende (0 ≤ x ≤ 0.15) phases undergo solid solution and variation in lattice parameters followed Vegard's law. The surface topography showed diffused grain polycrystalline texture with an overgrowth developed in some cases. The spectral studies of these films gave a continuous change in the optical gap (Eg = 1.76 to 1.45 eV ) with a band to band direct type of transitions.