Effects of annealing temperature on thermoelectric properties of Bi2Te3 films prepared by co-sputtering

N-type thermoelectric bismuth telluride (Bi2Te3) films were grown on SiO2/Si substrates by RF magnetron co-sputtering without intentional substrate heating. The effects of annealing temperature (150–350 °C) on surface morphology, crystal structure and thermoelectric properties of the Bi2Te3 films were investigated. Its crystallization was significantly improved by increasing the annealing temperature, giving rise to the enhanced charge carrier mobility. It is found that the optimum of Seebeck coefficient and power factor was about −242 μV/K and 21 μW/K2cm, respectively, obtained at the annealing temperature of 300 °C.