Influence of gamma radiation on the linear-nonlinear optical properties of Te₁₅Sn_2.5Se_82.5 thin film

Abstract This study examines the influence of γ -irradiation on the microstructural and optical properties of Te 15 Sn 2.5 Se 82.5 chalcogenide glass thin films. X-ray diffraction (XRD) analysis confirms the amorphous nature of the as-prepared films, while γ -irradiation induces structural reorganization, leading to the emergence of polycrystalline peaks. Optical characterization reveals that the pristine films exhibit low transmittance (1.8–6.2% at 2500 nm), which significantly increases (45%–62% at 2080 nm) with higher irradiation doses, suggesting reduced defect-mediated absorption. The direct optical bandgap decreases from 1.414 eV to 1.269 eV after irradiation, attributed to defect state formation and structural modifications. Optical conductivity analysis shows a gradual increase at lower doses (up to 100 kGy), followed by a sharp rise at higher doses, indicating enhanced carrier mobility due to irradiation-induced crystallization. These findings demonstrate that γ -irradiation effectively tunes Te-Sn-Se chalcogenide glasses’ optical and structural properties, making them promising for radiation-sensitive optoelectronic and infrared applications.