Room temperature MBE deposition of Bi2Te3 and Sb2Te3 thin films with low charge carrier densities

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 x 1019 cm-3. The in-plane transport properties were measured at room temperature, the thermopower was 130 μV K-1 for Sb2Te3 and -153 μV K-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. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)