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Abstracto

Influence of thickness on the structural and optical properties of cadmium selenide thin films

N. A. Okereke and A. J. Ekpunobi

The cadmium selenide (CdSe) thin films of thicknesses 1.31μm and 1.46μm were chemically deposited on well cleaned glass substrate at room temperature. The films are polycrystalline with hexagonal structure, confirmed by x-ray diffractogram. The optical spectra of cadmium selenide thin films were recorded in the wavelength range of 0.36μm and 1.10μm. The spectral absorption data shows that the films absorb in the ultra violet range of 0.36-0.45 microns and have low absorbance in VIS-IR regions of the spectrum. The films have average index of refraction of 2.2. The plot of α² versus hʋ showed a direct band gap range of 1.50eV-1.75eV. The band gap is found to increase with increase in film thickness.