Spectral properties of the silver photodoping process in thin As-S-Se layers

This paper deals with the optical properties of thin chalcogenide films from the ternary As33S67-xSex system depending on the composition and conditions of illumination using various light sources (white light, monochromatic light with lambda = 481, 514 (Ar+-laser) and 632.8 nm (He-Ne laser), respectively). The spectral dependence of the changes of the optical properties of thin As33S67-xSex layers with thickness d similar to 150-190 nm doped with silver were investigated. The optical constants (refractive index, n and extinction coefficient, k) were calculated applying double TR methods using both measured transmittance, T and reflectance, R spectra. The optical constants of single layers from chalcogenide glass and from silver have been used to calculate the reflectance spectrum of the unexposed As-S-Se/Ag bilayer system. Applying Tauc's law, the optical band gap, E-g and the structural parameter, B, related to the slope of the absorption edge, were determined.