Regensburg 2010 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 14: Thermoelectric Thin Films and Nanostructures II

DS 14.4: Vortrag

Dienstag, 23. März 2010, 15:00–15:15, H8

Half Heusler thin film superlattices for thermoelectrics — •Tino Jaeger¹, Christian Mix¹, Xenija Kozian², Benjamin Balke², Sascha Populoh³, Anke Weidenkaff³, Claudia Felser², and Gerhard Jakob¹ — ¹Institut für Physik, Universität Mainz, Staudinger ,Weg 7, 55099 Mainz, Germany — ²Institut für Anorganische Chemie und Analytische Chemie, Universität Mainz, Staudinger Weg 7, 55099 Mainz, Germany — ³EMPA - Eidgenössische Materialprüfung und -forschungs Anstalt Festkörperchemie und Katalyse, Ueberlandstrasse 129, 8600 Duebendorf, Switzerland

Due to rising energy costs and carbon dioxide concentration in the atmosphere interest on thermoelectric materials has strongly increased. The energy efficiency of thermoelectric devices has to be increased to expand the commercial usage. Here, efficiency is given by the figure of merit that is increased by a large Seebeck coefficient, large electrical conductivity and small thermal conductivity. Due to their electronic band structure half-Heusler alloys are appropriate candidates for such materials. Using thin film technology we prepare superlattices in order to increase the figure of merit. A superlattice based on NiTiSn and NiZr_0.5Hf_0.5Sn is supposed to decrease the thermal conductivity due to phonon scattering at the interfaces. The epitaxial multilayer structures are synthesized by sputter technique in argon atmosphere. A four-circle X-ray diffractometer allows the analysis of the crystal structures and the orientation of several layers with respect to each other. Resistivity, thermal conductivity and Seebeck coefficients are measured for different multilayers.