Room temperature MBE deposition of Bi2Te3and Sb2Te3thin films with low charge carrier densities

Sb2Te3and Bi2Te3thin films were grown at room temperature on SiO2substrates 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 × 1019cm−3. The in‐plane transport properties were measured at room temperature, the thermopower was 130 µV K−1for Sb2Te3and −153 µV K−1for Bi2Te3thin 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.