Berlin 2015 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 26: Layer Properties: Electrical, Optical, and Mechanical Properties
DS 26.11: Vortrag
Mittwoch, 18. März 2015, 17:45–18:00, H 2032
Detection of photoexcited hot charge carriers at the edges of metal nano films — •Marc Thomas1,2, Steffen Franzka2, Nils Hartmann2, Detlef Diesing1, Matthias Hensen3, Dominik Differt3, and Walter Pfeiffer3 — 1Institut für Physikalische Chemie, Universität Duisburg Essen — 2Interdisciplinary Center for Analytics on the Nanoscale, Universität Duisburg Essen — 3Institut für Experimentalphysik, Universität Bielefeld
Metallic nanostructures differ from metallic bulk materials concerning their electrical, optical and chemical properties. Structured nano films produced by evaporation through shadow masks exhibit thickness wedges at the edge of the nanostructure. A home-built microscope setup allows the laterally resolved scanning of the nanofilm’s reflectivity with a lateral resolution of 3 µ m . Experimentally observed reflectivity maps at the edge of the nanostructure are compared with calculated reflectivity maps derived by optical multi layer models taking into account the interference phenomena in nanostructures. When the structured metallic nano film is deposited on a metal–insulator sandwich, one can monitor photo excited hot charge carriers in the top nano film as a current in the backside metal under the oxide. This photocurrent is characterised with respect to the energy of the excited carriers by applying a bias voltage between the top metal nano film and the backside metal when scanning the edge of the metal nano structure by coupling a cw 532 nm laser to the microscope setup. Future applications of this technique as the spectral characterisation of localised optical excitations are addressed.