EXPLORING THE AMORPHOUS-TO-CRYSTALLINE PHASE TRANSITION IN Se80In ₅ Te15−xBi _<i>x</i> CHALCOGENIDE THIN FILMS

This study reports the transition from the amorphous to the crystalline phase in quaternary Se[Formula: see text]In 5 Te[Formula: see text]Bi x chalcogenide thin films prepared by controlled melt-quenching under a vacuum of 10[Formula: see text] Torr. Nonisothermal DSC measurements were performed to confirm the amorphous as well as glassy states of the synthesized Se[Formula: see text]In 5 Te[Formula: see text]Bi x alloys. For phase transformation, the thin films were thermally annealed for 2[Formula: see text]h at 343, 353, and 363[Formula: see text]K, after which Xray diffraction (XRD) and field emission scanning electron microscopy (FESEM) were used to characterize structural changes. Thermal annealing induced a substantial transformation from amorphous to crystalline morphology. With increasing annealing temperature, the luminescence peak showed a slight shift and an increase in intensity. The annealed films also exhibited higher absorption coefficients ([Formula: see text] and extinction coefficients ([Formula: see text], and a concomitant reduction in the optical band gap. The decrease in band gap with annealing temperature is attributed to the structural transition from the amorphous to the crystalline phase.