High temperature thermoelectric efficiency in Ba8 Ga16 Ge30

Eric S. Toberer, M. Christensen, B. B. Iversen, G. Jeffrey Snyder

Research output: Contribution to journalArticlepeer-review

121 Scopus citations

Abstract

The high thermoelectric figure of merit (zT) of Ba8 Ga16 Ge30 makes it one of the best n -type materials for thermoelectric power generation. Here, we describe the synthesis and characterization of a Czochralski pulled single crystal of Ba8 Ga16 Ge30 and polycrystalline disks. Measurements of the electrical conductivity, Hall effect, specific heat, coefficient of thermal expansion, thermal conductivity, and Seebeck coefficient were performed up to 1173 K and compared with literature results. Dilatometry measurements give a coefficient of thermal expansion of 16× 10-6 K-1 up to 1175 K. The trend in electronic properties with composition is typical of a heavily doped semiconductor. The maximum in the thermoelectric figure of merit is found at 1050 K with a value of 0.8. The correction of zT due to thermal expansion is not significant compared to the measurement uncertainties involved. Comparing the thermoelectric efficiency of segmented materials, the effect of compatibility makes Ba8 Ga16 Ge30 more efficient than the higher zT n -type materials SiGe or skutterudite Co Sb3.

Original languageEnglish (US)
Article number075203
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume77
Issue number7
DOIs
StatePublished - Feb 20 2008

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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