Studies of Se85Te12Bi3 and Se85Te9Bi6 Nanochalcogenide Thin Films at Different Working Pressures

In this research work, we have synthesized amorphous Se85Te12Bi3 and Se85Te9Bi6 Chalcogenide Glasses (ChGs) using melt quenching technique. The physical vapour condensation technique has been adopted for the synthesis of nanothin films of thickness 30 nm of synthesized samples at two different working pressures (1 torr and 3 torr) of ambient argon gas on the ultrasonically cleaned glass substrates. The temperature of the substrates was kept at 77 K (constant) using liquid nitrogen. The morphological analysis of the prepared nanochalcogenide thin films using FESEM confirmed that the particle size on the films was from 20 to 80 nm. We also observed more aggregation and reduction in particle size on the substrates with an increase in working pressure for both Se85Te12Bi3 and Se85Te9Bi6 nanothin films. HRXRD pattern confirmed the non-crystalline texture of synthesized nanothin films. Based on UV–Visible spectroscopy, the parameters related to optical characteristics like absorption coefficients and optical direct band gaps were measured for synthesized Se85Te12Bi3 and Se85Te9Bi6 nanochalcogenide thin films. A slight increment in the absorption coefficient and band gap with an increase in working pressure is observed for both Se85Te12Bi3 and Se85Te9Bi6 nanostructured thin films.