Effects of Heavy Ion Irradiation on the Thermoelectric Properties of In2(Te1−xSex)3 Thin Films

Ion irradiation is an exceptionally effective approach to induce controlled surface modification/defects in semiconducting thin films. In this investigation, ion-irradiated Se–Te-based compounds exhibit electrical transport properties that greatly favor the transformation of waste heat into electricity. Enhancements of both the Seebeck coefficient (S) and the power factor (PF) of In2(Te0.98Se0.02)3 films under 120 MeV Ni9+ ion irradiation were examined. The maximum S value of the pristine film was about ~221 µVK−1. A significantly higher S value of about ~427 µVK−1 was obtained following irradiation at 1 × 1013 ions/cm2. The observed S values suggest the n-type conductivity of these films, in agreement with Hall measurements. Additionally, Ni ion irradiation increased the PF from ~1.23 to 4.91 µW/K2m, demonstrating that the irradiated films outperformed the pristine samples. This enhancement in the TE performance of the In2(Te0.98Se0.02)3 system is elucidated by irradiation-induced effects that are revealed by structural and morphological studies.