Abstract
This article is dedicated to studying optical characteristics of thermally evaporated Pb10Se90-xGex (0.0 ≤ x ≤ 10.0 at.%) thin films. These films were deposited on pre-cleaned high-quality glass substrates under a vacuum about 5 × 10−4 Pa. The amorphous nature of films was affirmed by X-ray diffractograms. Elemental analysis was done by Energy-dispersive X-ray spectroscopy. Optical properties of Pb–Se-Ge films were studied and investigated using the transmission spectra. Thickness of the films and refractive index were computed utilizing Swanepoel envelope method. Wemple-Di-Domenico model was applied to get dispersion energies and oscillator parameters. Absorption coefficient values of films were estimated and found to be of the order of 10−4cm−1. The electronic transitions of a-Pb10Se90-xGex thin films were resulted from allowed indirect transitions and the optical band gap was found to decrease from 1.623 eV to 1.538 eV with increasing Ge-ratio while Urbach energy was found to increase from 61 meV to 86 meV. All discussed parameters strongly depend on the Ge-concentration.