Abstract
The study aims to present the physical characteristics and optical energy gap of the Ge10Se90-xTex thin films (where 0 <= x <= 70 at. %). Thermal evaporation technique is utilized for the preparation of amorphous thin films from the bulk of glasses. In the paper, the researchers have examined the density, molar volume, compactness, cohesive energy and distribution of the chemical bonds of the amorphous thin films theoretically. Within the spectral range from 400 to 1000 nm, the optical absorption spectra of as-prepared films have been evaluated. Furthermore, the study calculated absorption coefficient of thin films by using the absorption spectra to get the values of the optical energy gap and Urbach energy. It has been observed that the energy gap decreases from 1.88 to 1.17 eV due to the increase in Te content from 0 to 70 at. %. The outcomes of the study were found to be consistent with each other and are discussed thoroughly by using the chemical bond approach It has been noticed that the terms due to GeSe2 and SeTe are present in stoichiometric composition (Ge10Se55Te35), whereas in the case of non-stoichiometric compositions, excess Se or Te causes additional term that comes into effect.