Enhanced thermoelectric performance of SnTe film with optimized carrier transport induced by facile post-annealing process

Annealing treatment plays a vital role in tuning the microstructure and improving the performance of the thermoelectric film. In this work, SnTe thin films were fabricated by thermal evaporation technique and then annealed at a series of temperatures. The effects of annealing temperature on the element composite, surface morphology, crystal structure and thermoelectric properties were investigated. The electrical conductivity of the annealed films was increased while the Seebeck coefficient was declined slightly, due to the largely enhanced carrier concentrations and slightly reduced carrier mobility. In specific, the maximum Seebeck coefficient of 155 μV K⁻¹ and power factor of 29 μW cm⁻¹ K⁻² were achieved at the annealing temperature of 400 °C. Our results may provide an effective strategy to improve the properties of thermoelectric films.