Studies on phase change Ge₁₅Se₇₇Sb₈ thin films by laser irradiation

Ge₁₅Se₇₇Sb₈ chalcogenide thin films having thickness 300 nm were grown on glass/Si wafer by vacuum evaporation technique and induced by Transverse Electrical Excitation (TEA) laser for 10, 20 and 30 min. The synthesized Ge₁₅Se₇₇Sb₈ chalcogenide exhibited the glassy as well as amorphous nature, as evidenced in differential scanning calorimetry measurements. TEA laser irradiation on Ge₁₅Se₇₇Sb₈ thin films showed the polycrystalline nature while the as-prepared thin films were in amorphous nature. The optical band gap of as-prepared and laser irradiated films were determined by measuring the optical absorbance with photon energy. An increase in absorption coefficient and extinction coefficient was observed while the decrease in optical band gaps with laser irradiation time was demonstrated.