Berlin 2012 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 42: Thermoelectric materials IV: Glass, sintered materials (Focused session – Organizers: Meyer, Heiliger)

DS 42.5: Vortrag

Freitag, 30. März 2012, 12:45–13:00, H 2032

Laser sintering of nanoparticles - morphologic and thermoelectric aspects — •Benedikt Stoib¹, Tim Langmann¹, Martin S. Brandt¹, Nils Petermann², Hartmut Wiggers², and Martin Stutzmann¹ — ¹Walter Schottky Institut, Technische Universität München, Am Coulombwall 4, 85748 Garching — ²Institut für Verbrennung und Gasdynamik, Universität Duisburg-Essen, Lotharstraße 1, 47048 Duisburg

Bottom-up fabrication of nanoscale thermoelectrics in most cases requires annealing to improve the otherwise insufficient electrical performance. We apply a high-intensity short-pulse laser treatment to spin-coated films of crystalline nanoparticles, grown by plasma decomposition of silane and/or germane in a microwave reactor. The resulting films with sub-micrometer thickness are highly suited as a model system to systematically study the influence of Si/Ge ratio, doping, defects and grain size on the thermoelectrical potential of SiGe-based thin films. The morphology is discussed with special emphasis on porosity and its influence on macroscopic conductivity. The interdiffusion between nanoparticles of different composition during the partial melting is studied by Raman spectroscopy. The thermopower of the films indicates little variation of the Seebeck coefficient with respect to the morphological properties of the thin films.