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High temperature thermoelectric efficiency in Ba8Ga16Ge30

Toberer, Eric S. and Christensen, M. and Iversen, B. B. and Snyder, G. Jeffrey (2008) High temperature thermoelectric efficiency in Ba8Ga16Ge30. Physical Review B, 77 (7). Art. No. 075203. ISSN 1098-0121. doi:10.1103/PhysRevB.77.075203.

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The high thermoelectric figure of merit (zT) of Ba8Ga16Ge30 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 Ba8Ga16Ge30 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 Ba8Ga16Ge30 more efficient than the higher zT n-type materials SiGe or skutterudite CoSb3.

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Snyder, G. Jeffrey0000-0003-1414-8682
Additional Information:©2008 The American Physical Society. (Received 6 August 2007; accepted 8 October 2007; published 20 February 2008) We thank JPL-NASA, the Danish Research Council, and the Beckman Institute at Caltech for funding and V.A. Ravi for assistance with dilatometry measurements.
Subject Keywords:barium compounds; electrical conductivity; gallium compounds; Hall effect; Seebeck effect; thermal conductivity
Issue or Number:7
Record Number:CaltechAUTHORS:TOBprb08
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:9656
Deposited By: Archive Administrator
Deposited On:21 Feb 2008
Last Modified:08 Nov 2021 21:01

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