Study of CdSe_x Te_(1-x) thin films prepared by vacuum evaporation and their properties

CdSe x Te1-x films with different chemical composition ratio were prepared on glass substrates by vacuum evaporation. The elemental composition, surface morphology, crystal structure and optical property of the films were examined using EDX, XPS, SEM, XRD and UV-visible spectrophotometer. The effects of composition(x) and annealing on the films were analyzed. The studies reveal that the films exhibit a cubic zinc blende structure with(111) preferred orientation. Linear variation of lattice constant with composition(x) is observed. The optical band gap of the films decreases gradually with the increase of x passing through a minimum(1.41eV) for x =0.57 and then increases. The crystallization, optical transmittance and band gap of the films can be improved by increasing heat treatment temperature.