A hybrid substrate for surface-enhanced Raman scattering spectroscopy: Coupling metal nanoparticles to strong localised fields on a micro-structured surface

摘要

Electromagnetic coupling between localised plasmons on metal nanoparticles and the strong localised fields on a micro-structured surface is demonstrated as a means to increase the enhancement factor in surface-enhanced Raman scattering (SERS) spectroscopy. Au nanoparticles of diameter 20 nm were deposited on a micro-structured Au surface consisting of a periodic array of square-based pyramidal pits (Klarite). The spectra of 4-aminothiophenol (4-ATP) were compared before and after deposition of Au nanoparticles on the micro-structured surface. The addition of Au nanoparticles is shown to provide significantly higher signal intensities, with improvements of the order of ～10 ~3 per molecule compared with spectra obtained from the micro-structured substrate alone. This hybrid approach offers promise for combining nanoparticles with micro- and nano-structured surfaces in order to design SERS substrates with higher sensitivities.