Thermoelectric Properties of the Narrow-Gap Intermetallic Compound Ga2Ru: Effect of Re Substitution for Ru Atoms
Source: Journal of Electronic Materials, Volume 40, Number 5, May 2011 , pp. 1067-1072(6)
Abstract:In this paper, the effect of hole doping on the thermoelectric properties of the binary narrow-gap semiconducting intermetallic compound Ga2Ru in the temperature range from 373 K to 973 K was investigated. We synthesized sintered pellets by spark plasma sintering (SPS) after arc-melting and succeeded in preparing crack-free samples. The maximum dimensionless figure of merit ZT max was 0.50 at 773 K for the sintered Ga2Ru alloy. The temperature dependence of the electrical resistivity and its magnitude at 373 K dramatically changed from negative (~11,000 Ωcm) to positive (~200 Ωcm) upon hole doping by the substitution of Re for Ru atoms. Also, the Seebeck coefficient at 373 K changed from 300 V/K to 75 V/K. These changes were identified by the increase in carrier concentrations observed by Hall- effect measurements. In particular, large power factors (2.0 mW/m K2 to 3.0 mW/m K2) were obtained over a wide temperature range from 373 K to 973 K upon Re substitution. The lattice thermal conductivity beneficially decreased with increasing Re concentration as a result of an alloying effect.
Document Type: Research Article
Affiliations: 1: Department of Advanced Materials Science, The University of Tokyo, 502 Kiban-toh, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba, 277-8561, Japan, Email: email@example.com 2: Department of Space Biology and Microgravity Sciences, Japan Aerospace Exploration Agency, 2-1-1 Sengen, Tsukuba-shi, Ibaraki, 305-8505, Japan 3: Department of Advanced Materials Science, The University of Tokyo, 502 Kiban-toh, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba, 277-8561, Japan
Publication date: May 1, 2011