Münster 1999 – wissenschaftliches Programm

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O: Oberflächenphysik

O 22: Nanostrukturen

O 22.8: Vortrag

Mittwoch, 24. März 1999, 16:15–16:30, S1

Spectral Investigations of Intermittent Surface Enhanced Raman-Scattering (SERS) from Individual Silver Nanoclusters on a 25 millisecond Time Scale — •Jan U. Schmidt¹, Patrick J. Moyer², Waldfried Plieth³, and Alfred J. Meixner⁴ — ¹Institute of Applied Photophysics, University of Technology Dresden, Mommsenstrasse 13, 01069 Dresden, Germany — ²The University of North Carolina at Charlotte, Department of Physics, Charlotte, NC 28223,USA — ³Institute of Physical Chemistry and Electrochemistry, University of Technology Dresden, Mommsenstrasse 13, 01069 Dresden, Germany — ⁴University of Siegen, Dept. of Physical Chemistry I, 57068 Siegen, Germany

Surface-Enhanced Raman Scattering (SERS) spectra from nitrogen-based vibrational modes localized close to individually isolated silver (Ag) nanoclusters are studied on a time scale down to 25 ms. Nanoclusters of about 100 nm in diameter are electrochemically grown on a thin film of indium-tin-oxide deposited onto glass substrates. The Raman modes probed are attributed to residual Nitrogen-compounds adsorbed from the electrolyte solution onto the Ag nanoclusters. In addition to significant changes in the SERS-spectra, isolated nanoclusters show an intermittent on/off behavior. Both features are measured on a time scale of 25ms. Intermittent blinking behavior is further demonstrated by recording spectrally selective images with a confocal scanning microscope. Results are discussed in context of the electromagnetic SERS model.