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DS: Fachverband Dünne Schichten
DS 42: Thermoelectric Materials
DS 42.6: Vortrag
Donnerstag, 3. April 2014, 16:15–16:30, CHE 89
Full thermoelectric characterization and Lorenz number of individual metallic nanowires — •Rüdiger Mitdank1, Danny Kojda1, Zhi Wang2, Michael Kröner2, Peter Woias2, and Saskia F. Fischer1 — 1AG Neue Materialien, Humboldt-Universität zu Berlin, D-12489 Berlin, Newtonstr. 15 — 2Laboratory for Design of Microsystems, University of Freiburg , IMTEK, D-79110 Freiburg
A full characterization of the thermo electrical properties of nanowires (NWs) needs information about Seebeck coefficient as well as electrical and thermal conductivity. In order to determine the thermoelectric figure of merit of NWs, individual NWs are transferred to a micro machined measurement platform (TNCP) [1] and contacted by electron beam induced deposition (EBID) with platinum. A special issue of such measurements consists in the determination of the thermal conductivity (3-Omega-method). The compliance with boundary conditions and the presence of thermal contact resistances are discussed. Especially, we present a technique to determine the Lorenz number L from the ratio of two voltages. We observed a Lorenz number L smaller than the Sommerfeld value Ls. This difference increased with decreasing temperature. The deviation of L from Ls is compared with different models.
[1] Z. Wang et al., IEEE 26th Intern. Conf. on MEMS 2013, pp. 508.