Optical properties of CVD grown amorphous Ge–Sb–S thin films

Germanium antimony sulphide (Ge–Sb–S) amorphous thin films have been fabricated on commercial glass substrates by chemical vapour deposition (CVD). The compositions and thicknesses of these thin films have been characterized by micro-Raman, scanning electron microscope (SEM) and energy dispersive X-ray analysis (EDX) techniques. Optical transmission spectra measured by UV–VIS-NIR spectrometer have been used to determine the optical properties of these CVD-grown Ge–Sb–S amorphous thin films with Swanepoel’s methods. Optical band gaps of these films were calculated from Tauc’s extrapolation procedure. The dispersions of the refractive indices of these films have also been determined using the Wemple–DiDomenico method.