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O: Oberflächenphysik
O 48: Nanostructures IV
O 48.5: Vortrag
Freitag, 31. März 2006, 12:15–12:30, WIL A317
SERS substrates produced by tailormade metal nanoparticles using laser irradiation — •Blázquez Sánchez D.1, Gallasch L. 2, Schmidt H. 2, Kronfeldt H.D. 2, Hubenthal F. 1, and Träger F. 1 — 1Institut für Physik and Center for Interdisciplinary Nanostructure Science and Technology-CINSaT, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany — 2Institute of Optics, Technical University Berlin, Hardenbergstrasse 36, 10623 Berlin, Germany
New tailormade SERS substrates are presented which are based on precise control of the shape of nanoparticles (NPs) prepared by self-assembly of atoms on dielectric substrates. By applying nanosecond light pulses of appropriate fluence and wavelength oblate Ag or Au particles with a fixed shape have been fabricated. The method relies on the pronounced shape dependence of the absorption coefficient of metal NPs dominated by the excitation of surface plasmon polaritons. These resonances lead to a field enhancement in the vicinity of the particle surface, an effect widely exploited in surface enhanced Raman spectroscopy. With our manufacturing method, SERS substrates with tunable plasmon resonances can be simply produced for specific excitation wavelengths and detection ranges. Ag substrates were prepared here with and without a protective coating having a plasmon resonance at about 2.4 eV. SERS spectra of pyrene were obtained with excitation at 514 nm for all substrates indicating a good reproducibility. The substrates did not show degradation during the measurements and those with protective coatings yielded still 60 % of the SERS intensity of uncoated substrates indicating their potential usefulnes for the analytical detection of specific molecules.