Structural, optical, and physical properties investigations of Bi2Te3 topological insulator nanocomposites exposure to 60Co γ-rays

•Prepared Bi2Te3 nanocomposite by the Solvothermal method.•Studying the effect of γ- irradiation on the structural, morphological, and physical properties of Bi2Te3 nanocomposites.•γ- Irradiation doses have a great impact on the optical energy gap and other optical parameters.•The estimated values obtained from ESR show the effectiveness of the irradiation process on g-factor, hyperfine splitting, and the defect densities as well. Bi2Te3 nano-composites were accomplished by the solvothermal method and exposed to γ-rays (60Co source). XRD investigates the structural parameters of these nanostructured materials where SEM analysis confirms the nanostructured size and proves the change of the surface topography due to the irradiation process of the samples. The ESR exhibits the influence of the spins, Δg, and the number of defects for the pre-irradiated and post-irradiated Bi2Te3 samples. The optical properties, such as energy gap, refractive index, extinction coefficient, and dielectric constants, were obtained from the diffused reflectance data in the range between 200:800 nm. The optical energy gap for the pre-irradiated Bi2Te3 sample (0.72 eV) was the lowest, while the highest allowed energy gap was recorded for Bi2Te3/100 kGy sample (1.18 eV). The optical parameters were impinged on according to the change in the physical properties owing to the irradiation processing.