Nanoalloyed Bi 2Te 3, Sb 2Te 3 and Bi 2Te 3/Sb 2Te 3 multilayers

In this work, thin films of Bi 2Te 3 and Sb 2Te 3 were synthesized by the nanoalloying approach: Nanoscale layers of the elements Element nanoscale layers of Bi, Sb and Te are stoichiometrically deposited on a cold substrate using a MBE setup and subjected to an annealing process in which a solid state reaction yielding Bi 2Te 3 and Sb 2Te 3 takes place. Besides the two binary compounds, nanoscale multilayer (ML) stacks of 9 nm Bi 2Te 3/9 nm Sb 2Te 3 were created. The electrical transport properties of the binary compounds were determined in dependence of composition. Compound formation was directly observed in temperature-dependent in-situ XRD scans and was found to start at 100 °C. The stability of the Bi 2Te 3/Sb 2Te 3 ML nanostructure against temperature-driven interdiffusion during annealing was examined by SIMS and TEM for an annealing temperature of 150 and 250 °C, respectively. A comparative TEM study of the as grown and annealed state is presented.