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O: Fachverband Oberflächenphysik
O 37: Posters: Plasmonics, Electronic Structure and Spin-Orbit Interaction, Semiconductor and Insulator Surfaces, Nanostructures
O 37.18: Poster
Tuesday, April 1, 2014, 18:30–22:00, P2
Optimizing arrangements of a few Au-nanoparticles for SERS applications — •Kathrin Kroth, Thomas Sander, Sabrina Darmawi, Limei Chen, and Peter J. Klar — JLU Gießen
Surface-enhanced Raman spectroscopy (SERS) allows one to detect analytes on single-molecule level. The electric field of the impinging excitation light as well as the locally scattered light can be enhanced by several orders of magnitude in the gaps between metal-nanoparticles. SERS-substrates out of Au-nanoparticles have been prepared by combining top down nanofabrication with self-assembly of nanoparticles. At first a periodical array of cavities with different size and shape was fabricated by electron beam lithography (EBL) on a silicon substrate out of PMMA. The Au-nanoparticles from colloidal suspensions were arranged inside the cavities by a horizontal dip-coating process. The number and the orientation of the Au-nanoparticles in the cluster can be controlled by the size and shape of the PMMA-cavity. For the characterization of the different nanoparticle arrangements by Raman-imaging, a Raman-active molecule was deposited on top of the SERS-substrates allowing to study enhancement effects with respect to the nanoparticle arrangements and the polarization of the excitation light.