High thermoelectric power factor of SbPbTe thin alloy film grown by thermal evaporation and post-annealing treatment

Simple chemical compositions are frequently preferred in practical thermoelectric material applications due to their high growth success rates and increased stability. In this study, an n-type SbPbTe thin alloys film with equal amounts of all elements was grown, and the effect of equal contributions on thermoelectric properties and post-annealing treatment for 1–4 h was investigated. The as-grown SbPbTe thin alloys film and post annealed sample exhibited uniform composition distributions, single-phase microstructures, and non-uniform grain sizes at both micro- and nanoscales. The 4-h post annealed SbPbTe thin alloys film demonstrated maximum thermoelectric power factor of 21.2 μWcm⁻¹K⁻² at 500 K. This improvement was attributed to a decrease in electrical conductivity and the maintenance of a relatively maximum Seebeck coefficient achieved through the adjustment of carrier concentrations. The small grain size distribution over the surface contributed to strengthened grain boundary scattering, enhanced the charge carrier density and energy filtering effect. The thermoelectric power factor for the 4-h annealed sample peaks at 500 K, indicating optimal thermoelectric performance, as calculated from the Seebeck coefficient and electrical conductivity values. These findings provide insights into the structural and thermoelectric properties of SbPbTe thin alloy films, pointing to potential ways to improve their thermoelectric efficiency.