Structural and Optical Investigations of Amorphous Se_75-xTe₂₅Sb_x Thin Films

D. K. Dwivedi^1, , H. P. Pathak¹, R. K. Shukla² and A. Kumar²

¹Department of Physics, Amorphous Semiconductor Research Lab, M.M.M. Engineering College, Gorakhpur, India

²Department of Physics, H.B.T.I., Kanpur, India

Cite this paper:
D. K. Dwivedi, H. P. Pathak, R. K. Shukla and A. Kumar. Structural and Optical Investigations of Amorphous Se_75-xTe₂₅Sb_x Thin Films. American Journal of Materials Science and Engineering. 2013; 1(3):46-49. doi: 10.12691/ajmse-1-3-3

Abstract

Thin films of Se_75-xTe₂₅Sb_x (x = 0, 3, 6, & 9) glassy alloys 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 by 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 optical constants (absorption coefficient (α), extinction coefficient (k)) and optical band gap (E_g) have been studied. It has been found that extinction coefficient (k) decreases with increase in wavelength (λ). The absorption coefficient (α) is found to increase with incident photon energy. Optical band gap (E_g) has also been calculated and found to decrease with Sb content in Se_75-xTe₂₅Sb_x (x = 0, 3, 6, & 9) glassy system. The decrease of optical band gap (E_g) with Sb concentration has been explained on the basis of Mott and Davis model.

Keywords:
chalcogenide glasses amorphous semiconductors thin films optical properties optical band gap

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