Synthesis and post-annealing effects on the transport properties of thermoelectric oxide (ZnO)mIn2O3 ceramics

Abstract The synthesis and transport properties of n -type thermoelectric oxide (ZnO) m In 2 O 3 (Z m IO) ceramics prepared by conventional solid-state reaction method have been reported. It is found that the transport properties of Z m IO ceramics are very sensitive to the post-annealing temperature as well as the zinc content m . The resistivity of Z 5 IO annealed at 1400 °C decreases by more than 2 orders of magnitude in comparison with that of Z 5 IO annealed at 1200 °C, while the resistivities of Z 6 IO compounds annealed at 1250 and 1350 °C are more than 3 orders of magnitude larger than that of Z 6 IO annealed at 1300 °C. All the Z m IO compounds annealed at 1300 °C show electron-type conduction with a lowest resistivity at m  = 6. It is suggested that the oxygen defects or vacancies in the InO 2 layers play a major role on the carrier scattering mechanism, and the observed temperature-dependent resistivity for Z 5 IO and Z 6 IO compounds can be satisfactorily described by the variable-range hopping conduction. Furthermore, it is found that the values of Seebeck coefficient for Z m IO are also very sensitive to the zinc content m . The dimensionless figure of merit of 0.0045 at 300 K for m  = 6 has been obtained.