Tunable thermopower and thermal conductivity in Lu doped In2O3

Lu-doped polycrystalline (In(1-x)Lux)(2)O-3 (x = 0, 0.025, 0.05, 0.10, 0.15) materials were prepared by co-precipitation method followed by spark plasma sintering processing. The large and heavy Lu3+ was strategically selected to replace In3+ in order to lower the thermal conductivity while minimizing changes to the electronic structure of In2O3. The resulting samples had an average grain size of 200-400 nm at a density of similar to 90% of the theoretical mass density. Lu doping was found to increase the thermopower of In2O3, however the electrical resistivity was also increased, primarily due to the remarkable decrease in carrier concentration. The thermal conductivity of In2O3 was significantly reduced by the substitution of In by Lu.