Abstract：CdSyTe1-y (0≤y≤1) polycrystalline thin films were prepared on glass substrates by co-evaporation of powders of CdTe and CdS. For the characterization of the structure and composition of the CdSyTe1-y thin films the X-ray diffraction (XRD) and energy-dispersive spectroscopy (EDS) were used. The results indicate that the values of sulfur content y detected and controlled by the quartz wafer detector show good agreement with the EDS results. The films were found to be cubic for x<0.3,and hexagonal for x≥0.3. The 20-50 nm of grain sizes for CdSyTe1-y thin films were calculated using a method of XRD analysis. Finally,the optical properties of CdSyTe1-y thin films were characterized by UV-Vis-NIR spectroscopy alone. According to a method from Swanepoel,together with the first-order Sellmeier model,the thickness,of d-535 nm,energy gap of Eg-1.41 eV,absorption coefficient,α(λ) and refractive index,n(λ) of CdS0.22Te0.78 thin films were determined from the transmittance at normal incidence of light in the wavelength range 300-2 500 nm. The results also indicate that the CdSyTe1-y thin films with any composition (0≤y≤1) can be prepared by co-evaporation,and the method to characterize the optical properties of CdSyTe1-y thin films can be implemented for other semiconductor thin films.
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