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Author Yamashita, Osamu
Sponsorship (US)
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Publisher The American Physical Society
Language English
Subject Keyword MATERIALS SCIENCE ♦ ALLOYS ♦ ELECTRIC CONDUCTIVITY ♦ GRAIN BOUNDARIES ♦ HOT PRESSING ♦ MELTING ♦ PHYSICS ♦ THERMAL CONDUCTIVITY ♦ THERMOELECTRIC PROPERTIES
Abstract The Seebeck coefficient S, the electrical resistivity {rho} and the thermal conductivity {kappa} of Si{sub 0.95}Ge{sub 0.05} samples doped with 0.4 at.% P and/or 0.5{endash}2.0 mol% GaP, which were prepared by a conventional arc melting method, were measured as functions of GaP content and temperature T in the range from 323 to 1208 K. When multidoped with P and GaP, Ga tends to segregate more strongly with Ge to the grain boundaries than P, while when doped with GaP alone, both P and Ga segregate equally strongly with Ge. For multidoped samples, the S values at 323 K have a minimum at 1.0 mol% GaP and then increase with additional GaP, while the values of {rho} and {kappa} decrease monotonically with increasing GaP content. The optimum additional content of GaP that gives the largest thermoelectric figures of merit (ZT=S{sup 2}T/{kappa}{rho}) for multidoped n-type Si{sub 0.95}Ge{sub 0.05} samples was 1.5 mol%, which is slightly less than the 2.0 mol% of GaP added to Si{sub 0.8}Ge{sub 0.2} alloy by hot pressing. The ZT value for multidoped Si{sub 0.95}Ge{sub 0.05} with an optimum content of GaP increases linearly with temperature, and at 1073 K is 18% higher than that obtained previously for Si{sub 0.95}Ge{sub 0.05} doped with only 0.4 at.% P. At 1173 K the ZT value is 1.16, which corresponds to 95% of that obtained previously at the corresponding temperature for Si{sub 0.8}Ge{sub 0.2} alloy doped with 2.0 mol% GaP. {copyright} 2001 American Institute of Physics.
ISSN 00218979
Educational Use Research
Learning Resource Type Article
Publisher Date 2001-06-01
Publisher Place United States
Journal Journal of Applied Physics
Volume Number 89
Issue Number 11


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