Abstract
The purpose of this paper is to report the theoretical characterization and optical constants of the newly As30Se55Sb15-xCux (where x = 2.5, 5, 7.5 and 10 at%) thin films. Amorphous thin films were prepared from As30Se55Sb15-xCux ingots utilizing the thermal evaporation technique. The average coordination number, the number of constraints, the overall mean bond energy, the average heat of atomization, and the cohesive energy were examined theoretically. The optical transmission spectra for the as-prepared films have been measured in the spectral range from 400 to 2500 nm at normal incidence. Swanepoel method was utilized to obtain the refractive index and thickness of the As30Se55Sb15-xCux thin films. The absorption coefficient of the investigated films was calculated using the Connell and Lewis equation. It was found that the refractive index and the extinction coefficient of As30Se55Sb15-xCux films are influenced by increasing the copper content. Increasing the Cu content from 2.5 to 10 at% leads to a decrease of the energy gap from 1.61 to 1.42 eV.