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DS: Fachverband Dünne Schichten

DS 60: Thermoelectric Materials, Thin Films, and Nanostructures II (Focused Session -- Organisers: Nielsch, Rastelli, Balke)

DS 60.1: Vortrag

Freitag, 18. März 2011, 14:00–14:15, GER 37

Harman measurements on laser-annealed thin films of Si and Ge nanoparticles — •Benedikt Stoib¹, Martin S. Brandt¹, Nils Petermann², Hartmut Wiggers², and Martin Stutzmann¹ — ¹Walter Schottky Institut, Technische Universität München, Am Coulombwall 3, 85748 Garching — ²Institut für Verbrennung und Gasdynamik, Universität Duisburg-Essen, Lotharstraße 1, 47048 Duisburg

We discuss Harman measurements of the thermoelectric figure of merit ZT for thin films made of nanoscale Si, Ge and SiGe particles. The particles are prepared by plasma decomposition of silane and/or germane in a microwave plasma reactor and have a size of around 25 nm in the case of SiGe particles. Thin films are prepared by a drop-casting process on quartz substrates, followed by an annealing step with a high intensity pulsed laser. Films with µm-range thicknesses are subjected to a specific current cycle at varying temperature. The Harman method is known to directly yield the thermoelectric figure of merit ZT under certain conditions. In this contribution, we show temperature-dependent measurements suggesting values of ZT > 0.3 at 650 K for SiGe. The presented data are discussed taking into account possible parasitic effects.