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O: Fachverband Oberflächenphysik
O 60: Poster Session IV (Solid/liquid interfaces; Semiconductors; Oxides and insulators; Graphene; Plasmonics and nanooptics; Electronic Structure; Surface chemical reactions; Heterogeneous catalysis)
O 60.91: Poster
Wednesday, March 16, 2011, 17:30–21:00, P4
Structural changes of percolated metal films by laser irradiation — Christian Maasem, •Daniela Schneevoigt, Florian Hallermann, and Gero von Plessen — Institute of Physics (IA), RWTH Aachen University, 52056 Aachen, Germany
In semi-continuous, percolated metal films, both localised and propagating surface-plasmon modes can be excited by light irradiation over a wide spectral range. This can lead to strong optical field enhancements which are confined to ’hot spots’ of a few nanometers in size.
In this work, we show that percolated silver films on glass substrates change their structure upon irradiation with focussed laser light. The irradiated areas exhibit more light scattering and higher light transmission than non-irradiated areas. This could point towards an aggregation of the films to larger structures and thus towards a reduction of the coverage of the substrate surface. Even after an additional coating with SiO2, changes of the structure of the silver films occur already at low laser intensities.
In contrast, no changes are observed when irradiating percolated gold films. Thus, it can be assumed that the restructuring of the film material is not purely a thermal effect.