Temperature-dependent optical functions of selected Ge-Sb-Se bulk chalcogenide glasses obtained by spectroscopic ellipsometry

Abstract

In this paper, we present spectroscopic ellipsometry measurements of five selected bulk chalcogenide glasses (Ge28Sb6Se66, Ge19Sb17Se64, Ge12Sb25Se63, Ge28Sb12Se60 and As40Se60) for broad wavelength range (0.3-15 mu m) at the temperatures from room temperature up to glass transition temperature (with reserve). Temperature dependence of bandgap energy obtained from Tauc-Lorentz oscillator together with temperature dependence of refractive index for selected wavelengths (1.55, 3.4, 7.0 and 10.6 mu m) where the studied materials are transparent are presented together with thermo-optic coefficients dEg/dT and dn/dT for these wavelengths.