Thermoelectric properties of polycrystalline Zn4Sb3 samples prepared by solid state reaction method

Seebeck coefficient S(T), electrical resistivity rho(T) and thermal conductivity kappa(T) measurements on polycrystalline Zn4Sb3 compounds grown by solid state reaction method are presented; these transport properties were studied in the temperature range between 100 and 290K. The Seebeck coefficient is positive over the measured temperature range and its magnitude increases with both temperature and the processing time up to reach values close to 240 mu V/K. The electrical resistivity shows a weak semiconducting behavior. its magnitude increases with the processing time to reach values around 10 m Omega cm in the sample annealed during 5 h, then rho(T) decreases up to 0.5 m Omega cm. The thermal conductivity shows a linear temperature behavior, at room temperature, it reaches minimum values close to 0.5 W/K m. From rho(T), S(T) and kappa(T) data, it was possible to determine the thermoelectric power factor, PF and the dimensionless figure of merit ZT, which reach maximum values close to 14 mu W/K-2 cm and 0.2, respectively. The behavior of studied transport properties shows that these Zn4Sb3 compounds can be prepared by using the solid state reaction method, which could allow to obtain proper samples to be used in technological thermoelectric applications. (C) 2008 Elsevier B.V. All rights reserved.