Gamma irradiation impact on structure and electrical properties of Te 75 S 15 Bi 10 alloy

The impact of gamma (γ) irradiation (500, 1000, and 1200 Gy) from a 60Co source on the structural, morphological, and electronic transport characteristics of synthesized Te75S15Bi10 alloys was systematically investigated. Structural evaluations via X-ray diffraction (XRD) and scanning electron microscopy (SEM) demonstrated a radiation-driven lattice consolidation, resolved as a monotonic expansion in average crystallite size from 18.4 to 36.2 nm and substantial grain coarsening with systematic porosity reduction from 14.2% to less than 3.8% at the maximum dose. Temperature-dependent direct current (DC) electrical transport measurements resolved two distinct thermally activated conduction regimes across the 292–455 K range, confirming the coexistence of localized hopping and extended-state conduction channels. Quantitative density of states (DOS) profiling revealed that the localized state density (N(Eloc)) decreased from 8.59× 1016 to 1.91× 1016 ev−1.cm−3 upon irradiation up to 1200 Gy, while the extended state density (N(Eext)) maintained a stable semiconductor framework of ∼ 1019 ev−1.cm−3. Ultimately, these coordinated reconfigurations confirm that controlled high absorbed gamma doses effectively drive the ternary matrix from a strained amorphous-like baseline into a highly consolidated radiation-tolerant polycrystalline structure.