Nanoalloyed Bi_2Te_3, Sb_2Te_3 and Bi_2Tei/Sb_2Te_3 Multilayers

摘要

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.