Thermoelectric properties of low-temperature-grown polycrystalline InAs1−xSbx films

Abstract

The development of thin-film thermoelectric generators for micro-energy harvesting is highly anticipated. In this study, we have investigated the synthesis and thermoelectric applications of ternary alloy InAs1−xSbx thin films, which are narrow-gap III–V compound semiconductors. Polycrystalline InAs1−xSbx thin films with sub-micrometer grain size were synthesized on glass using molecular-beam deposition at 400 °C with all composition x. The InAs1−xSbx thin films exhibited n-type conduction, and their electrical and thermoelectric properties were strongly dependent on x and the amount of Sn doping. The ternary alloying reduced the power factor and contributed to a reduction in thermal conductivity. The InAs0.2Sb0.8 thin film on a glass substrate exhibited a power factor of 100 μW m−1 K−2 and a thermal conductivity of 2.0 W m−1 K−1 at room temperature. Furthermore, a comparable performance was demonstrated for an InAs0.2Sb0.8 thin film grown on a plastic film. These achievements will pave the way for the application of III–V compound semiconductors in flexible thermoelectric generators.