Growth and Optical Characterization of DVT Grown SnSe0.5Te0.5 Single Crystals

Abstract

In present investigation, we report the growth of SnSe0.5Te0.5single crystals by direct vapor transport (DVT) technique. The main requirement of this technique is precise adjustment of the temperature gradient between two zones of a horizontal furnace to enhance the transport of material in vapour form. For structural characterization, X-ray diffraction technique is used and it is found that this material is crystallized in orthorhombic structure. The values of lattice parameters, unit cell volume and X-ray density are calculated and presented. For optical characterization, absorption spectra of thin flake like crystals have been taken by using UV-VIS-NIR Spectrophotometer in the wave number range 200 nm to 2000 nm at room temperature with the incident plane polarized light beam normal to the basal plane i. e. along the c-axis of the grown flakes of SnSe0.5Te0.5single crystals. Direct as well as indirect band gap has been calculated near the fundamental absorption edge. Optical parameters such as transmittance (T), reflectance (R), refractive index (η) and extinction coefficient (k) have been determined and represented here from the measured value of absorbance of this crystal within said wavelength range.