LAUSR

Abstract Highly oriented Bi2-xSbxTe3 (x = 0, 0.7, 1.1, 1.5, 2) ternary nanocrystalline films were fabricated using vacuum thermal evaporation method. Microstructures and morphologies indicate that Bi2-xSbxTe3 films have pure rhombohedral phase with well-ordered nanopillars array. Bi, Sb and Te atoms uniformly distributed throughtout films with no precipitation. Electrical conductivity of Bi2-xSbxTe3 films transforms from n-type to p-type when x > 1.1. Metal-insulator transition was observed due to the incorporation of Sb in Bi2Te3. Bi2-xSbxTe3 film with x = 1.5 exhibits optimized electrical properties with maximum electrical conductivity σ of 2.95 × 105 S m−1 at T = 300 K, which is approximately ten times higher than that of the undoped Bi2Te3 film, and three times higher than previous report for Bi0.5Sb1.5Te3 films and bulk materials. The maximum power factor PF of Bi0.5Sb1.5Te3 nanopillars array film is about 3.83 μW cm−1 K−2 at T = 475 K. Highly oriented (Bi,Sb)2Te3 nanocrystalline films with tuned electronic transport properties have potentials in thermoelectric devices.