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In the present work, we probe into the phase transition of amorphous Bi10As40Se50 to a crystalline one upon thermal annealing. The Bi10As40Se50 thin films were prepared through thermal evaporation method and were annealed at 130° for 5h. The as-prepared and annealed films were characterized by XRD, FESEM and Raman spectroscopy. X-ray diffraction study revealed the amorphous nature of the as-prepared film and Bi3Se4 crystallite phase formation in the annealed film. This clearly indicates annealing induced diffusion of Bi into As2Se3 and hence the formation of Bi3Se4 phase. FESEM images show the smooth and homogeneous surface for the Bi10As40Se50 film whereas the annealed film shows these crystallites covers the surface. The Raman spectra shows a broad band corresponds to AsSe3 unit and a raman peak of bismuth selenide in the asprepared film whichshows shifting in case of annealed film. [ABSTRACT FROM AUTHOR]

Thin films of a-Se66Te25In9 have been deposited onto a chemically cleaned glass substrate by thermal evaporation technique under vacuum. Glassy nature of the films has been ascertained by X-ray diffraction pattern. The analysis of absorption spectra, measured at normal incidence, in the spectral range 400-1100 nm has been used for the optical characterization of thin films under investigation. The effect of thermal annealing on structure and optical band gap (Eg) of a-Se66Te25In9 have been studied. [ABSTRACT FROM AUTHOR]

Thin films of a-Se72Te25Sb3 were prepared by vacuum evaporation technique in a base pressure of 10-6 Torr on to well cleaned glass substrate. a-Se72Te25Sb3 thin films were annealed at different temperatures below their crystallization temperatures for 2h. The structural analysis of the films has been investigated using X-ray diffraction technique. The optical band gap of as prepared and annealed films as a function of photon energy in the wavelength range 400-1100 nm has been studied. It has been found that the optical band gap decreases with increasing annealing temperatures in the present system. [ABSTRACT FROM AUTHOR]