Structural and optical properties of (Ge11.5 Se67.5 Te12.5)100-x Sbx (0 ≤ x ≤ 30) chalcogenide glasses: A material for IR devices

Chalcogenide based glasses are active materials for infrared imaging and semiconducting devices due to their large transparency in infrared regions. Present paper focus on the characteristics of Ge-Se-Te glasses doped with Sb with chemical composition (Ge-11.5 Se-67.5 Te-12.5)(100-x) Sb-x (x = 0, 10, 20, 30) obtained by conventional melt-quench technique. The structural characteristics were determined by XRD and SEM-EDX technique while the differential scanning calorimetry (DSC) proves the binary role of Sb in prepared glassy compound. FTIR spectroscopy confirms the impurities in glassy compound by different absorption bands. The wide optical transmitting windows of 2.5-20 mu m by FTIR enable its application in IR devices. The optical constants were determined by using the transmittance and reflectance spectra of the prepared samples which were recorded using UV-Vis spectrophotometer. Addition of Sb increases the absorption and extinction coefficient while optical band gap first increases and then increases. The value of Urbach energy and refractive index decreases by increasing Sb mol% which was explained on the behalf of semiconducting properties.