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Keywords:

  • EDX;
  • MBE;
  • point defects;
  • TEM;
  • thermoelectric effects;
  • thin films

Abstract

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 × 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.