Fabrication and Structural Characterization of Se-Ge Chalcogenide Glasses by Means of Melt Quenching Technique

In this study, the structural and optical characterization of Se-Ge alloys during melt quenching technique have been investigated. For this purpose, five different samples of Se100-xGex (x= 10, 20, 30, 40, 50) were prepared by conventional melt quenching in quartz ampoule. The produced samples were characterized using X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), IR Variable Angle Spectroscopic Ellipsometry (IR-VASE) and Raman Spectroscopy. The results showed that the glass forming ability of Se70Ge30 and Se50Ge50 is so low and the structures of these alloys after quenching are combination of amorphous, GeSe2 and Ge2Se3 compounds. Although the structure of as-prepared Se90Ge10, Se80Ge20 and Se60Ge40 is fully amorphous, only Se60Ge40 shows IR transmittance (with transmittance higher than 55% between 0.8-11 μm). The refractive index of this glass was in the range of 2.0 to 2.6 and it was decreased with increasing the wavelength. The Fermi energy, Urbach energy, indirect and direct band gaps values of Se60Ge40 glass were estimated about 0.3879, 0.1526, 1.345 and 1.28 eV, respectively.