Effects of working pressure during magnetron sputtering on thermoelectric performance of flexible p-type Bi0.5Sb1.5Te3 thin films

The influence of argon working pressure during magnetron sputtering on thermoelectric properties has been investigated on p-type Bi0.5Sb1.5Te3 flexible films deposited at various working pressures in the range from 2 to 5 Pa. The microstructure and orientations, atomic compositions, and carrier concentration could be regulated by adjusting the working pressure, due to the size-dependent inhibition of the deposition of the sputtered Bi, Sb, and Te atoms from argon ions. Profiting from the occurrence of the (006) orientation, the nearest stoichiometric ratio, the highest carrier concentration and mobility, and the quantum confinement effect, the film deposited at 4 Pa displays the maximum power factor of 1095 μW m−1 K−2 at 360 K. These results suggest that the electrical transport properties of the sputtered flexible thermoelectric thin films can be synergistically optimized by selecting an appropriate working pressure.