Investigation of low-temperature thermoelectric properties of Si0.8Ge0.2 alloy irradiated by high energy electron beam

Abstract

In this work, electron beam (EB) irradiation has been significantly used to alter the structure and transport properties of Si0.8Ge0.2 alloys to improve thermoelectric behaviour, doses ranging from (0–40 kGy). Compared to the pristine sample the resistivity of the EB irradiated sample increases, this may be due to the increase in lattice distortion induced by the EB irradiation, which leads to a decrease in mobility of the charge carriers. Further, the resistivity decreases for higher EB irradiation samples (20 kGy and 40 kGy), this may be due to an increase in hole concentration (p) induced by EB irradiation, which dominates the mobility (μ). The Seebeck coefficient value reveals the p-type nature of the alloy, which increased with EB irradiation. The occurrence of metallicity and increase in the Seebeck coefficient is understood due to the bombardment-induced defects. The alloy exhibits the maximum power factor of 287.76 μW/mK2 at 320 K under a 40 kGy EB dosage.