Optical properties change in Te diffused As₅₀Se₅₀ chalcogenide thin film

In the present report, we present the effect of Te diffusion into As₅₀Se₅₀ thin film which changes the optical properties. The Te/As₅₀Se₅₀ film was irradiated by a laser beam of 532 nm to study the diffusion mechanism due to photo induced effect. The As₅₀Se₅₀, Te/As₅₀Se₅₀ films show a completely amorphous nature from X-ray diffraction study. A non direct transition was found for these films on the basis of optical transmission data carried out by Fourier Transform infrared Spectroscopy. The optical bandgap is found to be decreased with Te deposition and photo darkening phenomena is observed for the diffused film. The change in the optical constants are well supported by the corresponding change in different types of bonds which are being studied by X-ray photoelectron spectroscopy.