Berlin 2012 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 43: Thermoelectric materials V: Bulk materials (Focused session – Organizers: Meyer, Heiliger)
DS 43.7: Vortrag
Freitag, 30. März 2012, 15:15–15:30, H 2032
TiNiSn and Zr0.5Hf0.5NiSn superlattices for thermoelectrics — •Tino Jaeger1, Michael Schwall2, Xeniya Kozina2, Benjamin Balke2, Sascha Populoh3, Anke Weidenkaff3, Claudia Felser2, and Gerhard Jakob1 — 1Institut für Physik, Universität Mainz, 55099 Mainz — 2Institut für Analytische und Anorganische Chemie, Universität Mainz, 55099 Mainz — 3EMPA, Ueberlandstrasse 129, 8600 Duebendorf, Switzerland
In order to increase the attractiveness of thermoelectric devices, their efficiency must be increased. Beside others, the properties of the thermoelectric material can be improved. That can be achieved by either increasing Seebeck coefficient or conductivity or by a depressed thermal conductivity along the thermal gradient. For thin films, superlattices or multilayers can be used to lower the cross plane thermal conductivity. As a bottom up approach, artificially layered films with a periodicity of about 5-6 nm are assumed to generate the most phonon scattering at the interfaces. If electrical properties remain unchanged or less effected, the thermoelectric efficiency is enhanced. Semiconducting Half-Heuslers are well studied thermoelectric bulk materials. Among others, TiNiSn and Zr0.5Hf0.5NiSn are potential candidates. Essentially, their similar lattice constants enable epitaxial layers on top of each other. Furthermore, varied atomic masses of Ti, Zr and Hf generate the aspired alternating mass distribution. By rotating the substrate in between simultaneously burning cathodes, significant film thicknesses can be achieved by sputter deposition.