TY - JOUR
T1 - Thermoelectric properties of the narrow-gap intermetallic compound Ga 2Ru
T2 - Effect of Re substitution for Ru atoms
AU - Takagiwa, Yoshiki
AU - Okada, Junpei Tamura
AU - Kimura, Kaoru
N1 - Funding Information:
This work is partly supported by the Thermal & Electric Energy Technology Foundation (TEET), KAKENHI No. 21860021 from JSPS and Scientific Research on Priority Areas of New Materials Science Using Regulated Nano Spaces, KAKENHI No. 19051005 from MEXT.
PY - 2011/5
Y1 - 2011/5
N2 - In this paper, the effect of hole doping on the thermoelectric properties of the binary narrow-gap semiconducting intermetallic compound Ga 2Ru 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 Ga 2Ru alloy. The temperature dependence of the electrical resistivity and its magnitude at 373 K dramatically changed from negative (∼11,000 μΩcm) to positive (∼200 μΩcm) upon hole doping by the substitution of Re for Ru atoms. Also, the Seebeck coefficient at 373 K changed from 300 μV/K to 75 μV/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 K 2 to 3.0 mW/m K 2) 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.
AB - In this paper, the effect of hole doping on the thermoelectric properties of the binary narrow-gap semiconducting intermetallic compound Ga 2Ru 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 Ga 2Ru alloy. The temperature dependence of the electrical resistivity and its magnitude at 373 K dramatically changed from negative (∼11,000 μΩcm) to positive (∼200 μΩcm) upon hole doping by the substitution of Re for Ru atoms. Also, the Seebeck coefficient at 373 K changed from 300 μV/K to 75 μV/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 K 2 to 3.0 mW/m K 2) 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.
KW - Nowotny chimney ladder
KW - Thermoelectric properties
KW - narrow-band-gap semiconductor
KW - ruthenium gallide
KW - spark plasma sintering
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U2 - 10.1007/s11664-011-1543-y
DO - 10.1007/s11664-011-1543-y
M3 - Article
AN - SCOPUS:79955897565
SN - 0361-5235
VL - 40
SP - 1067
EP - 1072
JO - Journal of Electronic Materials
JF - Journal of Electronic Materials
IS - 5
ER -