Effects of Heavy Ion Irradiation on the Thermoelectric Properties of In₂(Te_1-xSe_x)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(Te_0.98Se_0.02)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(Te_0.98Se_0.02)₃ system is elucidated by irradiation-induced effects that are revealed by structural and morphological studies.