Spectroscopic studies of (AsSe)_(100-x)Ag_x thin films

摘要

Thin (AsSe)_(100-x)Ag_x films have been grown onto quartz substrates by vacuum thermal evaporation or pulsed laser deposition from the corresponding bulk materials. The amorphous character of the coatings was confirmed by X-ray diffraction investigations. Their transmission was measured within the wavelength range 400-2500 nm and the obtained spectra were analyzed by the Swanepoel method to derive the optical band gap E_g and the refractive index n. We found that both parameters are strongly influenced by the addition of silver to the glassy matrix: E_g decreases while n increases with Ag content. These variations are discussed in terms of the changes in the atomic and electronic structure of the materials as a result of silver incorporation.