Photoluminescence and transmittance of CdS1−xTex thin films

CdS1−xTex thin films were prepared by first producing CdS:In thin films by the spray pyrolysis (SP) technique and then annealing the films in the presence of Te vapor in nitrogen atmosphere. X-ray diffraction (XRD) measurements showed that the films are polycrystalline with mixed (cubic and hexagonal) structure. Transmittance measurements were recorded at room temperature in the wavelength range 400–1100 nm. The first derivative of the absorbance – which was deduced from the transmittance – was calculated and used to find the values of the bandgap energy. The presence of two minima in the first derivative curves was interpreted by the presence of a mixed (hexagonal and cubic) phase in accordance with the XRD measurements. The photoluminescence was recorded at T=60 K and a deconvolution peak fit was performed for each spectrum. The dependence of the PL spectra on the tellurium content of the films is obvious through the number, position and amplitude of the peaks in the different bands.