Thermoelectric performance of lanthanum telluride produced via mechanical alloying
Abstract
Lanthanum telluride (La3−xTe4) has been synthesized via mechanical alloying and characterized for thermoelectric performance. This work confirms prior reports of lanthanum telluride as a good high-temperature thermoelectric material, with zT~1.1 obtained at 1275 K. The thermoelectric performance is found to be better than that of SiGe, the current state-of-the-art high-temperature n-type thermoelectric material. Inherent self-doping of the system allows control over carrier concentration via sample stoichiometry. Prior high-temperature syntheses were prone to solute rejection in liquid and vapor phases, which resulted in inhomogeneous chemical composition and carrier concentration. The low-temperature synthesis provides homogeneous samples with acceptable control of the stoichiometry, and thus allows a thorough examination of the transition from a heavily doped degenerate semiconductor to a nondegenerate semiconductor. The effect of carrier concentration on the Hall mobility, Seebeck coefficient, thermal and electrical conductivity, lattice thermal conductivity, and thermoelectric compatibility are examined for 0.03<=x<=0.33.
Additional Information
©2008 The American Physical Society. (Received 30 April 2008; revised 25 June 2008; published 19 September 2008) The authors thank the JPL Thermoelectrics Group for help with various measurements and Sossina Haile for useful discussions regarding material processing. They thank Teruyuki Ikeda for performing the electron microprobe measurements and Chi Ma of the Caltech GPS Analytical Facility for discussions regarding the ZAF correction employed. Richard Blair is acknowledged for useful discussions regarding mechanical alloying and crystallite size determination, as are J. Aldrich and Y. Bar-Cohen for providing equipment and assistance with the ultrasonic measurements. The work described in this paper was performed at the Jet Propulsion Laboratory, California Institute of Technology under a contract with the National Aeronautics and Space Administration.Attached Files
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2008-09-20Created from EPrint's datestamp field
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2021-11-08Created from EPrint's last_modified field