Significantly reduced lattice thermal conductivity and enhanced thermoelectric performance of In2O3(ZnO)3 ceramics by Ga2O3 doping

Abstract

The In2O3(ZnO)3+x mol%Ga2O3 (x = 0, 0.1, 0.3, 0.5, 1) ceramics were synthesized by a solid-state reaction process. The effect of Ga doping on the thermoelectric properties of the In2O3(ZnO)3 ceramics was studied. The phase structure and microstructure of all the bulk samples were checked by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM), respectively. Additionally, the minimum thermal conductivity of 1.45 Wm−1K−1 at 973 K is obtained for 0.5% Ga-doped sample, which is 35% lower than that of the pristine sample. The significantly decreased thermal conductivity for Ga2O3-doped sample is due to the enhanced scattering of phonons, which is derives from the point defects caused by Ga-doping and the introduction of the second phase. As a result, the In2O3(ZnO)3+0.5 mol% Ga2O3 sample achieved the highest ZT value of 0.23 at 973 K.