Thermoelectric properties of oxide solid solutions based on Al-doped ZnO

Investigation on thermoelectric properties of oxide solid solutions based on Zn_0.98Al_0.02O revealed that the thermal conductivity of Al-doped ZnO was markedly suppressed via formation of solid solution, particularly for those with MgO. The decrease in the thermal conductivity was significant at the lower temperatures, and at room temperature (Zn_0.9Mg_0.1) _0.98Al_0.02O attained a value less than a quarter of that for Zn_0.98Al_0.02O However, the electrical conductivity also decreased, while the Seebeck coefficients almost unchanged. The Hall measurements revealed reduction in both the carrier concentration and the Hall mobility for the solid solution samples. In spite of the significant suppression of the thermal conductivity, improvement in the figure of merit was unsuccessful for the MgO-doped samples because of the unfavorable decrease in the electrical conductivity