Optical properties of GeSeTl thin films

Using the usual melt-quenching technique, glasses with composition Ge14Se86-xTlx (x = 20%, 22%, 23.5%, 25%, 26.5% and 28%) have been obtained to prepare thin films with different thicknesses (d = 15, 30, 60, 90, 120 and 180 nm) using electron-beam evaporation. The optical gap Eg was found to decrease with increasing thallium content, x. It is found also that thicker films are accompanied with larger optical gaps. The refractive index n was found to increase with increasing Tl ratio and to decrease with increasing thickness of the films