Electronic and thermal transport in GeTe [electronic resource] : A versatile base for thermoelectric materials
- Published
- Washington, D.C. : United States. Dept. of Energy. Office of Science, 2013.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy. - Additional Creators
- Ames Laboratory, United States. Department of Energy. Office of Science, and United States. Department of Energy. Office of Scientific and Technical Information
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- Restrictions on Access
- Free-to-read Unrestricted online access
- Summary
- GeTe is a narrow-band gap semiconductor, where Ge vacancies generate free charge carriers, holes, forming a self-dopant degenerate system with p-type conductivity, and serves as a base for high-performance multicomponent thermoelectric materials. There is a significant discrepancy between the electronic and thermal transport data for GeTe-based materials reported in the literature, which obscures the baseline knowledge and prevents a clear understanding of the effect of alloying GeTe with various elements. A comprehensive study including XRD, SEM, EDS, Seebeck coefficient, electrical resistivity, thermal conductivity, and 125Te NMR of several GeTe samples was conducted. Similar Seebeck coefficient and electrical resistivity are observed for all GeTe samples used showing that the concentration of Ge vacancies generating charge carriers is constant along the ingot. Very short 125Te NMR spin-relaxation time agrees well with high carrier concentration obtained from the Hall effect measurements. Our data show that at ~700 K, GeTe has a very large power factor, 42 μWcm-1K-2, much larger than that of any high efficiency thermoelectric telluride at these temperatures. Electronic and thermal properties of GeTe are compared to PbTe, another well-known thermoelectric material, where free charge carriers, holes or electrons, are generated by vacancies on Pb or Te sites, respectively. Discrepancy in the data for GeTe reported in literature can be attributed to the variation in the Ge:Te ratio of solidified samples as well as to different conditions of measurements.
- Report Numbers
- E 1.99:is-t-8116
is-t-8116 - Subject(s)
- Note
- Published through SciTech Connect.
08/29/2013.
"is-t-8116"
Journal of Applied Physics 114 083713 ISSN 0021-8979 AM - Funding Information
- AC02-07CH11358
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