Abstract
Surfaces prepared by vacuum depositing silver on silica nanospheres were investigated as surface-enhanced Raman scattering (SERS) substrates using benzoic acid as an analyte. The SERS sensitivity of the substrates was probed as a function of substrate parameters, such as silver-film thickness and silica-bead dimensions. The SERS signals were found to increase with an increase in silver-film thickness and silica-bead diameter until a maximum signal was reached. Additional increases in the film thickness or the bead diameter resulted in a decrease in the SERS signal. Maximum SERS response was obtained with a substrate made by vapor depositing a 6 nm thick coating of silver on a thin layer of silica beads with a nominal diameter of 565 nm. Scanning electron microscopy (SEM) of the substrates was performed to consider the effect of surface morphology on the SERS responses. Optimal SERS substrates exhibited a detection limit of 5 × 10-7 M for adsorbed benzoic acid. A linear relationship was demonstrated between the SERS response and the concentration of benzoic acid with two different slopes, one in the 10-5-10-3 M range and the other in the 10-3-10-1 M range. Published in 2003 by John Wiley & Sons, Ltd.
Original language | English |
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Pages (from-to) | 394-398 |
Number of pages | 5 |
Journal | Journal of Raman Spectroscopy |
Volume | 34 |
Issue number | 5 |
DOIs | |
State | Published - May 1 2003 |
Keywords
- Benzoic acid
- Silica beads
- Silver films
- Surface-enhanced Raman scattering