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Thin films of Bi2Te3 and Sb2Te3 were synthesized by the nanoalloying approach, which has recently been proven to yield VVI compounds with good thermoelectric properties and has several advantages over conventional growth on hot substrates. Firstly, repeating layers of the elements Bi, Sb and Te with a thickness in the range between 0.2 nm and 2.4 nm were deposited on BaF2 (111) substrates in an MBE system at room temperature with different deposition patterns for different samples, i.e. in bilayer and quintuple stacks, with different starting layer thicknesses and different Te contents. Subsequently, the element layer stacks were annealed in order to induce crystallization and compound formation of Bi2Te3 and Sb2Te3 thin films. The annealed thin films were characterized using X-ray diff ractometry (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The transport properties, i.e. electrical conductivities, carrier concentrations, carrier mobilities, Seebeck coefficients and thermal conductivities, were determined at room temperature for several sets of starting layer thicknesses and deposition patterns depending on the Te content. The texture was found to be strongly influenced by the starting thicknesses of the elemental layers in the deposition pattern. Results of temperature dependent measurements of the Seebeck coefficient and electrical conductivity on one sample of nanoalloyed Bi2Te3 and Sb2Te3 together with results from temperature dependent in situ XRD investigations are presented

Sb2Te3 and Bi2Te3 thin films were grown at room temperature on SiO2 substrates using MBE and were subsequently annealed at 250°C. The films were stoichiometric, polycrystalline, textured, and yielded strikingly low charge carrier densities of about 2.7 × 10(exp 19) cm-3. The in-plane transport properties were measured at room temperature, the thermopower was 130 µVK(exp -1) for Sb2Te3 and -153 µVK(-1) for Bi2Te3 thin films. The small charge carrier densities are explained by a reduced antisite defect density due to the low temperatures to which the thin films were exposed during annealing