Transport coefficients of (Bi1-xSbx)(2)Se-3 single crystals

(Bi1-xSbx)(2)Se-3 (x = 0.0 to 0.2) single crystals were prepared using a modified Bridgman method. Measurements of the Hall coefficient R(H), electrical conductivity sigma and Seebeck coefficient alpha showed that incorporation of the antimony atoms into the Bi2Se3 crystal lattice results in an increase in the free electron concentration for a low antimony content, whereas the free electron concentration is suppressed in the range of a high antimony content. This effect is explained qualitatively by changes in the concentrations of point defects in the (Bi1-xSbx)(2)Se-3 crystals. We assume that the substitution of Bi atoms by Sb atoms results in a decrease in the concentration of Se vacancies V-Se(..) and antisite defects Bi-Se'. The course of the dependences of ln (R(H) sigma) vs ln T manifests that in the temperature region of 100-400 K transport properties of the studied crystals are characterized by a mixed transport mechanism of free carriers, mainly on acoustical phonons and ionized impurities.