An experimental and computational study for enhancement in optical nonlinearity and dielectric behaviour in thermal annealing induced Ag diffusion at Ag/Sb-S-Se interface

Abstract

The annealing induced Ag diffusion into Sb40Se30S30 film brings enormous changes in its linear-nonlinear optical along with the structural and dielectric properties which is reported in the current study. The prepared Ag/Sb40Se30S30 film was annealed at different temperatures like 100,150,200 and 250 °C. The structure remained amorphous one as confirmed from XRD while the particle size increased with annealing as observed from FESEM images. The Raman study depicts the microstructural change in terms of shift in vibrational peaks. The optical study was done by UV–Vis-NIR spectrometer from which different optical parameters were evaluated. The decrease in optical bandgap with increase in linear refractive index is accompanied by the increase in optical density, extinction coefficient and decrease in skin depth. The dielectric loss factor increased while the quality factor decreased with annealing. The static dielectric constant increased with the increase in carrier concentration. Both the electrical as well as optical conductivity are found to be increased while optical electronegativity and plasma frequency decreased with annealing. The 3rdorder nonlinear susceptibility and non-linear refractive index are doubled with annealing while there is decrease in nonlinear absorption coefficient. The surface wettability study infers the hydrophilic nature sustains with annealing. The computational analysis using the DFT method was carried out to provide some necessary information about the structure and physical properties of the prepared materials.