Dresden 2011 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 43: Poster II: Thin Film Chalcogenide Photovoltaics; Thermoelectric Materials, Thin Films, and Nanostructures
DS 43.6: Poster
Mittwoch, 16. März 2011, 15:00–17:30, P2
The potential of phase change materials for thermoelectric applications - An investigation of alloys along the pseudo binary line from GeTe to SnTe — •Felix Lange, Hanno Volker, Karl Simon Siegert, and Matthias Wuttig — 1. Physikalisches Institut IA, RWTH Aachen University
Thermoelectric generators make use of the Seebeck effect which is an intrinsic property of any non dielectric solid. Materials with a high conversion efficiency are characterized by a high figure-of-merit ZT=σ S2/κ, where σ is the electrical conductivity, S the Seebeck coefficient and κ the thermal conductivity.
We have recently shown that phase change materials employ resonant bonding [1] which results in a delocalization of carriers and an anharmonic potential [2]. The delocalization of carriers leads to high electrical conductivity while the anharmonic potential enhances the probability for phonon-phonon interactions such as umklapp processes. Hence, phase change materials are promising candidates for thermoelectric applications.
Therefore alloys along the pseudo binary line from GeTe to SnTe are investigated. It is shown, that the electrical conductivity can be tailored by gradually adding Sn. The disorder on the Ge-Sn sublattice causes a low thermal conductivity which develops a minimum for Ge2Sn2Te4.
[1] K. Shportko et al., Nature Materials 7, 653-658 (2008)
[2] D. Lencer et al., Nature Materials 7, 972-977 (2008)