Thermoelectric properties of the narrow-gap intermetallic compound Ga 2Ru: Effect of Re substitution for Ru atoms

Yoshiki Takagiwa, Junpei Tamura Okada, Kaoru Kimura

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)1067-1072
Number of pages6
JournalJournal of Electronic Materials
Volume40
Issue number5
DOIs
Publication statusPublished - 2011 May 1
Externally publishedYes

Keywords

  • Nowotny chimney ladder
  • Thermoelectric properties
  • narrow-band-gap semiconductor
  • ruthenium gallide
  • spark plasma sintering

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Materials Chemistry

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