Investigation of microstructural, optical, physical properties and dielectric relaxation process of sulphur incorporated selenium-tellurium ternary glassy systems

The present study explores the consequence of incorporation of sulphur content on the structural, linear, and non-linear optical properties as well as dielectric behaviour of the amorphous chalcogenide glassy materials having chemical composition xS-(1-x) (0.65Se-0.35Te) for x = 0.1, 0.2, and 0.3. The samples have been synthesized through the quenching of the melt technique. X-ray diffraction patterns reveal that some nano crystallites are superimposed on amorphous glass matrices. Rietveld refinement data validates the presence of Te0.5Se0.5 and Se0.44S0.56 nanophases. Field Emission Scanning Electron Microscopy image confirms the formation of nanocrystallites and amorphous structure. Optical absorbance measurements have been performed, and several optical parameters are evaluated. The obtained bandgap energies are found to increase with the incorporation of S (x). The third-order nonlinear susceptibility and nonlinear refractive index are calculated from the linear parameters using semi-empirical relations. The topological concept has been used to correlate the dependence of mean coordination numbers with some of the obtained parameters. The dielectric constant and dielectric loss also have been studied over a wide range of frequency and temperature. The complex electrical modulus study reveals that the conductivity relaxation process is non-Debye type, whereas, scaled modulus spectra point out the conductivity relaxation process is temperature independent.

Automated summary

The study investigates the impact of sulphur content on the structural, linear, and non-linear optical properties, as well as dielectric behavior of amorphous chalcogenide glassy materials. The incorporation of sulphur was found to increase the bandgap energy and affect various optical parameters. Analysis using topological concept revealed correlations between mean coordination numbers and obtained parameters, while the study showed that the conductivity relaxation process is non-Debye type.