Characterization of Al-doped ZnO thermoelectric materials prepared by RF plasma powder processing and hot press sintering

RF plasma processing technique was used to prepare Al-doped (up to 4 at%) ZnO nanopowders. The as-prepared powders were subsequently hot pressed to form sintered pellets. The temperature-dependent electrical and thermal properties of the sintered materials were measured from room temperature to 800 °C. All the doped samples showed metallic electrical conductivity and the overall thermoelectric performances were comparable to doped ZnO thermoelectric materials obtained by other nanoprocessing techniques. The results showed that RF plasma processing technique can be effectively used to produce doped nanopowders. The thermoelectric performance of the doped samples was discussed and related to the microstructure of the materials.