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

Abstract

Abstract Sb 2 Te 3 and Bi 2 Te 3 thin films were grown at room temperature on SiO 2 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 19 cm −3 . The in‐plane transport properties were measured at room temperature, the thermopower was 130 µV K −1 for Sb 2 Te 3 and −153 µV K −1 for Bi 2 Te 3 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.