Investigation of CdSe x Te1−x : Te composite thin films

Thin films of the composite CdSe_xTe_1–x : Te have been prepared by the thermal coevaporation technique of ingot double-source CdSe powder and Te at 300 K. The films were analyzed by energy dispersion analysis by X-rays (EDAX) and X-ray diffraction techniques and found to have a polycrystalline structure of CdSe_xTe_1–x of hexagonal phase and Te of hexagonal phase for CdSe_xTe_1–x : Te of x ranging from 0.65 to 0.76. There exists SiO₂ of tetragonal phase in as-deposited CdSe : Te films but it is not present in films annealed at a temperature of 413 K. The crystallite size for the composite films was determined and showed the same values for different x values. Optical properties of deposited films were calculated through their optical transmission and reflection spectra. It was observed that the composite films of CdSe_xTe_1–x : Te have two direct transition energies instead of one direct optical transition typical of CdSe films.