TRANSPORT-PROPERTIES ANALYSIS OF SINGLE-CRYSTALS (BIXSB1-X)2TE3 GROWN BY THE TRAVELING HEATER METHOD

A modeling of the transport properties of p-type (BixSb1-x)2 Te3 single crystals is presented. Reasonably good agreement between calculated and experimental transport coefficients was achieved by considering a single valence band and acoustic phonon and ionized impurity scattering for holes. The anisotropy of the transport coefficients, in directions perpendicular (11) and parallel (33) to the trigonal c-axis of the crystals, was also taken into account in the model. The effective masses m(ij) the isotropic and anisotropic energy independent relaxation time factors tau(oac) and tau(oionii) for the main directions (ii = 11 or 33) were determined for two solid solutions with x = 0.2 and 0.25. The lattice thermal conductivities were estimated for the two solid solutions. The maximum room temperature figure of merit was estimated at 3.2 x 10(-3) K-1 for a solid solution with x = 0.225 in good agreement with the experimental results.