Düsseldorf 2007 – scientific programme

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MO: Fachverband Molekülphysik

MO 53: New Experimental Techniques

MO 53.5: Talk

Thursday, March 22, 2007, 15:15–15:30, 6D

Surface Enhanced Raman Scattering (SERS) on Lithographically Fabricated Nano-Structured Gold Surfaces — •Malte Sackmann, Torsten Balster, and Arnulf Materny — International University Bremen (Jacobs University Bremen as of spring 2007), Germany

Raman spectroscopy is a valuable tool for the characterization of molecular properties and for chemical analysis. However, for low concentrations standard Raman techniques cannot be used. Making use of the enhancement of the Raman scattered signal by rough silver or gold surfaces or nano clusters the vibrational spectra even of extremely small amounts of substances could be detected. Due to the unpredictable characteristics of these substrates SERS (Surface Enhanced Raman Scattering) was nearly exclusively used for qualitative investigations. Recently, we have published first results on SERS using lithographically fabricated nano-structured gold surfaces (2dim dot gratings). However, the experimentally found enhancement factors were smaller than the expected ones by a factor of 1000. Therefore, we have now concentrated on a systematic investigation of the Raman enhancement. For this, parameters like dot sizes, shapes, and spacings were varied to find the maximum enhancement factors and also to gain better insight into the mechanisms contributing to the SERS effect. In our contribution we discuss the results of these experiments. Special emphasis is put on the question, how reproducible SERS spectra can be obtained using such well-defined substrates. This would be of great importance for possible applications in quantitative chemical analysis.