Abstract
The present work aims to study theoretically the effect of Sn content on many physical parameters, such as coordination number (CN), constraints number (CON), overall mean bond energy () and cohesive energy (CE) for Ge25Se65Sb10-xSnx (where 0 <= x <= 10 at. %) glasses. Likewise, optical constants of the thin films were evaluated via the use of the Swanepoel technique. It is found that, CN, CON, , and CE increase by increasing the Sn content. This behavior is obvious evidence for increasing the rigidity of the Ge25Se65Sb10-xSnx glasses by increasing the Sn content. The chemical bonds occurred within the Ge25Se65Sb10-xSnx glasses have been estimated. It was found that, the heteropolar bonds occurred in the examined glasses are Sn-Se, Ge-Se and Sb-Se which have energies 58.818, 49.441 and 43.981 kcal/mol., respectively. The obtained values of the refractive index (n) of the films were fitted to the two-term Cauchy dispersion equation to get the single oscillator (E-o) and dispersion (E-d) energies. In addition, values of the absorption coefficient (alpha) are obtained using the conditions suggested by Connell and Lewis. An increase of the Sn content from 0 to 10 at. % prompts a decrease of the energy gap (E-g) from 1.79 to 1.40 eV.