Thermoelectric Properties of Binary Semiconducting Intermetallic Compounds Al₂Ru and Ga₂Ru Synthesized by Spark Plasma Sintering Process

Abstract

The authors report the electrical and thermal transport properties of binary semiconducting intermetallic Al₂Ru and Ga₂Ru compounds from 373 to 973 K. We synthesized sintered pellets of Al₂Ru and Ga₂Ru by the spark plasma sintering (SPS) method, resulted in a removal of small amount of a secondary phase and of cracks. The maximum Seebeck coefficient of Al₂Ru and Ga₂Ru shows a large positive value of 200 μV/K and 360 μV/K, respectively. In particular, a large power factor ∼2.8 mW/m-K² was obtained at 773 K in Ga₂Ru compound. The dimensionless figures of merit ZT of sintered Al₂Ru and Ga₂Ru samples monotonically increase with increasing temperature and reach a maximum value of 0.20 and 0.45 at about 873 K and 773 K, respectively.