Structural and optical properties of SeGe and SeGeX (X = In, Sb and Bi) amorphous films

The optical properties of Se0.62Ge0.38 and Se0.62Ge0.35X0.03 where [X = In. Sb and Bi] thin films has been investigated Thin films used in these studies were thermally evaporated on glass substrates. The structural characterization revealed that the as-deposited films were amorphous in nature. The chemical composition of the films has been checked using energy dispersive X-ray spectroscopy (EDX). The spectral distribution and optical parameters have been investigated using spectrophotometric measurements of transmittance and reflectance in the wavelength range (400-2500 nm). The optical constants were determined from the interference maxima and minima using the Swanepole method. The dispersion of the refractive index is discussed in terms of Wemple-Didomenico single oscillator model. The analysis of the optical absorption data indicates the existence of allowed indirect transitions. The optical dispersion parameters E-0 and F-d were determined according to the above-mentioned model. The optical constants such as optical band gap E-g(opt), complex dielectric constant and dissipation factor tan 6 were determined. 0 2009 Elsevier B.V All rights reserved.