Carrier transport phenomenon and thermoelectric properties in melt-grown tellurium doped n-type Bi0.88Sb0.12 alloy

We report the carrier transport phenomenon and thermoelectric properties in tellurium (Te) doped Bi0.88Sb0.12. Two types of samples were prepared with 0.5 and 1 mol% Te. The structural analysis was carried out by XRD, transmission electron microscope, and energy dispersive spectroscopic techniques. The transport properties were evaluated through the temperature dependent resistivity and thermopower measurements with room temperature Hall and thermal conductivity. The negative values of Hall coefficients and degenerate behavior showed the effectiveness of Te as an n-type dopant in Bi0.88Sb0.12. The room temperature dimensionless figure of merit was found to be in the range of 5.8 x 10(-3)-5.71 x 10(-2). The enhancement in thermoelectric figure of merit by one order of magnitude is found due to lower doping of Te. The temperature dependent behavior of the resistivity and thermopower was correlated and explained by the thermal excitation of the dopant atoms from the unionized to ionized states. (C) 2014 Elsevier B.V. All rights reserved.