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DS: Fachverband Dünne Schichten

DS 61: Thermoelectric Materials, Thin Films, and Nanostructures III (Focused Session -- Organisers: Nielsch, Rastelli, Balke)

DS 61.5: Vortrag

Freitag, 18. März 2011, 17:00–17:15, GER 37

Complex Chalcogenides for Thermoelectrics: Microstructure Analysis of AgPb₁₈SbTe₂₀ — •Susanne Perlt¹, Thomas Höche¹, Jayaram Dadda², and Eckhard Müller² — ¹Leibniz Institute of Surface Modification, Leipzig — ²German Aerospace Center, Institute of Materials Research, Köln

The thermoelectric (TE) bulk material AgPb₁₈SbTe₂₀ (LAST-18) is a highly promising candidate for application in the mid-temperature range. The manufacturing process needs to be controlled in such a way, that the figure of merit, ZT [1], gets maximized. In this respect, a high electronic conductivity σ, a high thermopower S, and a low thermal conductivity κ are crucial. The high TE performance of LAST is assumed to be caused by the nanoscale precipitates formed by nucleation and growth and/or spinodal decomposition [2].
The presented LAST samples are fabricated via different melting routes and annealing treatments in order to find favourable conditions, i.e. to get a homogeneous material on the microscale but introduce precipitates on the nm scale.
Based on properties monitored by a Seebeck scanning microprobe, structure-property relationships are studied by SEM and TEM analysis. Site-specific lift-out of TEM lamellae are made by focused ion beam (FIB) machining. High-resolution STEM is giving insight into the atomistic structure of the nanostructures.
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