Enhanced power factor of Bi0.5Sb1.5Te3 thin films via PbTe incorporating and annealing

Improving the thermoelectric properties of bismuth telluride based thin films is of great significance for promoting their commercial applications. In this work, Bi0.5Sb1.5Te3/PbTe composite films with high orientation were prepared by magnetron co-sputtering. The carrier concentration and the electrical conductivity can be increased by adjusting the amount of PbTe. The subsequent annealing was observed to improve the thin films crystalline and leads to the appearance of the PbTe phase, which optimizes the carrier concentration and mobility, and then improves the electrical conductivity and Seebeck coefficient synergistically. As a result, the highest power factor about 2.06 mW/mK(2) was obtained at 480 K in the Bi0.5Sb1.5Te3/PbTe composite film containing 0.6 % Pb after the annealing at 300 degrees C for 1h, which is nearly 5 times as much as that of the parent Bi0.5Sb1.5Te3 film.