Structure and enhanced thermoelectric properties of InGaO3(ZnO)m (m=1, 2, 3, 4, and 5) ceramics.

InGaO 3 (ZnO) m (m = 1, 2, 3, 4, and 5) ceramics are a series of n-type oxide thermoelectric materials with layered structures and low thermal conductivities. Herein, InGaO 3 (ZnO) m (m = 1, 2, 3, 4, and 5) ceramics were fabricated by spark plasma sintering (SPS). Two different trends in the thermoelectric properties of the InGaO 3 (ZnO) m (m = 1, 2, 3, 4, and 5) ceramics were observed depending on the odevity of the m value. The InGaO 3 (ZnO) sample exhibited a relatively high electrical conductivity and was therefore selected for vacuum annealing to further improve the electrical transport performance. Oxygen vacancy defects were introduced to the matrix during the annealing procedure, which improved the thermoelectric performance. A maximum ZT of 0.45 was obtained at 973 K for the InGaO 3 (ZnO) sample with a 96 h vacuum annealing treatment, which is 30 times higher than that of the pristine sample. [ABSTRACT FROM AUTHOR]