Morphology of Silver and Gold “SERS Active” Substrates from Optical Spectroscopy Experiments and Numerical Simulations
✍ Scribed by Félidj, N. ;Aubard, J. ;Lévi, G.
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 184 KB
- Volume
- 175
- Category
- Article
- ISSN
- 0031-8965
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✦ Synopsis
In order to understand more deeply the surface enhanced Raman scattering (SERS) effect, we develop different models allowing the determination (i) of the morphology of silver or gold clusters in colloidal sols from their ultraviolet±visible extinction spectra and (ii) of the roughness features of silver islands chemically deposited on various metals from differential reflectivity measurements. For ultraviolet±visible absorption spectra, the model leads to calculated spectra of aggregated colloids in good agreement for both profiles and intensities with experimental ones and allows to approach the histogram of the clusters appearing in the aggregated colloid. This histogram reveals that the aggregated sols mainly consist of small spheres, reflecting unaggregated particles, and of elongated spheroids formed by the coalescence of several spherical particles. In the last part of this paper, we present preliminary results showing how to obtain ``SERS active substratesº by chemically depositing silver islands onto various metals (Zn, Al, Cu). The observed SERS spectra are qualitatively related to the differential reflectivity spectra obtained on the same substrates.