Thermoelectric properties of polycrystalline samples prepared by solid state reaction method

Abstract

Abstract Seebeck coefficient S ( T ) , electrical resistivity ρ ( T ) and thermal conductivity κ ( T ) measurements on polycrystalline Zn 4 Sb 3 compounds grown by solid state reaction method are presented; these transport properties were studied in the temperature range between 100 and 290 K. 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 μ V / K . The electrical resistivity shows a weak semiconducting behavior, its magnitude increases with the processing time to reach values around 10 m Ω cm in the sample annealed during 5 h, then ρ ( T ) decreases up to 0.5 m Ω cm . The thermal conductivity shows a linear temperature behavior, at room temperature, it reaches minimum values close to 0.5 W/K m. From ρ ( T ) , S ( T ) and κ ( 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 μ W / K 2 cm and 0.2, respectively. The behavior of studied transport properties shows that these Zn 4 Sb 3 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.