The high-energy gamma-ray irradiation treatment using Co-60 isotope offers the possibility of engineering mechanical and optoelectronic properties of In Bi0.8Te0.2crystals. Tellurium-doped indium bismuthide(In Bi) crystals were prepared by horizontal directional freezing technique. Dose-dependent modifications in structure, composition and surface topographical features have been analyzed by X-ray powder diffraction, X-ray energy-dispersive analysis, transmission electron and atomic force microscopy, respectively. Dielectric constant and dielectric loss were found to increase with the cumulative dose of radiation, and a shift in the ferroelectric transition temperature(Tc) from 405 to 410 K was observed for25 k Gy. Upon irradiation, there is an enhancement in microhardness(HV), yield stress(ry) and stiffness constant(C11).The optical transmittance was decreased by 12.45%, resulting in a reduction in the optical band gap from 0.210 e V to0.198 e V. These results indicate the suitability of In Bi0.8Sb0.2crystals for low-wavelength infrared applications. The high-energy gamma-ray irradiation treatment using Co-60 isotope offers the possibility of engineering mechanical and optoelectronic properties of In Bi 0.8 Te 0.2 citrystals. -dependent modifications in structure, composition and surface topographical features have been analyzed by X-ray powder diffraction, X-ray energy-dispersive analysis, transmission electron and atomic force microscopy, respectively. Dielectric constant and dielectric loss were found to increase with the cumulative Given irradiation, there is an enhancement in microhardness (HV), yield stress (ry) and stiffness constant (C11) The optical conductivity was decreased by 12.45%, resulting in a reduction in the optical band gap from 0.210 e V to 0.98 e V. These results indicate the suitability of In Bi0.8Sb0.2crystals for low-wavelength infrared applications.