Regensburg 2010 – scientific programme
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DS: Fachverband Dünne Schichten
DS 14: Thermoelectric Thin Films and Nanostructures II
DS 14.4: Talk
Tuesday, March 23, 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 NiZr0.5Hf0.5Sn 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.