Structural and optical properties of Agx(GeSe3)100-x films fabricated by sputtering method

Abstract

The effect of Ag content on the structural and optical properties for Agx(GeSe3)100-x films which were prepared by sputtering method was presented in this paper. The X-ray diffraction (XRD) spectra, optical transmission spectra and Raman spectra of the films were measured, and optical absorption spectra could be obtained from optical transmission spectra. The optical band gaps (Egout) and refractive index were calculated through the Tauc’s law and Swanepoel method based on the optical transmission spectra, parameter K was constant which depended on the transition probability, the Urbach energy (Eu) was derived from the exponential part of the optical absorption edge. It is shown that both Egout and Tauc slopes (K1/2) decrease with the increase of Ag content, while Eu exhibits an opposite trend. Analyses of Raman spectra and exponential part of the absorption edge show that Ag addition increases the density of Ag-Se bond and the Eu in the amorphous films, which results in the decrease of Egopt. In addition, the changes of the refractive indices are also discussed. The results indicate that the present research can be helpful to further understanding of the structure and optical properties of the material.