Enhanced thermoelectric performance of P-type SnTe thin film through Sr doping and Post-Annealing treatment

Abstract

Lead-free tin telluride (SnTe) has gained significant attention for its potential use in mid-temperature thermoelectric power generation. In this work, we systematically analyzed the thermoelectric power factor of Sn0.7Sr0.3Te thin films at various post-annealing temperatures through structural, morphological, and thermoelectric property measurements. Our findings show that Sr-doping in the SnTe thin film matrix and post-annealing treatment can significantly enhance the thermoelectric properties by modifying the band structure and introducing an energy-filtering effect at grain boundaries. We achieved a maximum power factor of 29.4 μWm-1K−2 at 523 K for Sn0.7Sr0.3Te thin films post-annealed at 1073 K, which is three times greater than that of pure SnTe. This work demonstrates that Sr-doping and post-annealing effects can tune the band gap, induce band degeneration, and reduce grain size, resulting in a high thermoelectric power factor of the SnTe thin film.