Compositional dependence of the optical properties of chalcogenide glasses thin film of Agx(Ge0.25Se0.75)100-x system

J.M. CONDE-GARRIDO; A. PIARRISTEGUY; M.A. UREÑA; M. FONTANA; B.ARCONDO; A. PRADEL

St. Malo

Simposio; XVIII International Symposium on Non-Oxide Glasses and New Optical Glasses; 2012

Chalcogenide glasses have many technological applications as a result of their particular optical and electrical properties. These materials possess remarkable optical properties such as wide transmission windows (1?20 mm) controlled by composition, large refractive indexes and interesting photo-induced properties. In this work, the effect of silver content on the optical properties of films of Agx(Ge0.25Se0.75)100-x chalcogenide glasses has been analysed. The films were prepared by pulsed laser deposition from bulk glasses target of composition Agx(Ge0.25Se0.75)100-x with x≤ 25 at.% and deposited onto microscope slides. Morphology, structure and optical properties of the films were characterised by means of the following techniques: profilometry, scanning electron microscopy and UV-visible-NIR spectroscopy. The optical constants, i.e. the refractive index, extinction coefficient, absorption coefficient, and the optical band gap energy were determined and their compositional dependence was considered. The refractive index of the films between 500 nm and 2500 nm was determined from the transmission spectra of the stacked structure ??film-substrate?? using procedures described previously by Swanepoel and González-Leal [1,2]. The optical band gap was also calculated with Tauc?s law [3]. It was found that as the Ag content of the alloy increased, the refractive index increased (for every wavelength) and the optical band gap decreased.