Facile synthesis of preferential Bi_0.5Sb_1.5Te _3.0 nanolayered thin films with high power factor by the controllable layer thickness

Layer-by-layer assembly of nanostructured Bi_0.5Sb _1.5Te₃ thin films were prepared by a simple magnetron sputtering method. X-ray diffraction investigations revealed that all the thin films were well crystallized with preferred orientation along (00l) direction. Scanning electron microscopy images indicated that nanostructure of the condensed films was stacked by tens of parallel repeating layers. Meanwhile, the particular thicknesses of layers could be controlled in the range of 20-140 nm by adjusting the deposition time. The electrical conductivity and power factor were significantly increased compared with those of ordinary thin films, while the maximum power factor reached 53 μW cm^-1 K^-2 when the layer thickness was 40 nm. The multi-layered materials are promising candidates for miniaturized modules with their unique properties.