Dresden 2011 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 101: Particles and clusters II

O 101.2: Vortrag

Freitag, 18. März 2011, 11:30–11:45, WIL C107

Surface enhanced Raman spectroscopy using tailored noble metal nanoparticles — •Robert Ossig, Frank Hubenthal, and Frank Träger — Institut für Physik and Center for Interdisciplinary Nanostructure Science and Technology -- CINSaT, Universität Kassel, Kassel, Germany

Surface enhanced Raman spectroscopy (SERS) is a powerful technique in the field of molecular spectroscopy, which exploits the superior optical properties of metal nanoparticles. In principle SERS allows to detect and to measure spectra of single molecules. However, stable and reproducible SERS substrates, which are necessary for routine applications, are only rarely available. Furthermore, to achieve the optimum enhancement for certain excitation wavelength and molecule combinations, a tailoring of the optical properties is desired. To meet these requirements, our samples were produced by Volmer-Weber growth, in combination with laser tailoring. The combination of both methods allows a tuning of the surface plasmon resonance of the metal nanoparticles in the vicinity of the excitation wavelength for the SERS measurements, independently from the nanoparticle size. Hence, the influence of the wavelength on the SERS spectra can be studied. In this contribution we present SERS measurements of pyrene as a function of the excitation wavelengths. We will show that for all excitation wavelengths the SERS spectra are highly reproducible and strongly enhanced, if tailored nanoparticles serve as substrates. However, only for an excitation wavelength near the infrared, a background free Raman signal with an excellent signal-to-noise ratio is achieved.