Silver particles on stochastic quartz substrates providing tenfold increase in Raman enhancement

Exceptionally strong Raman enhancements have been observed for molecules adsorbed on silver deposited onto etched quartz substrates. A stochastic arrangement of tall quartz posts, with an average spacing of approx. 110 nm, is obtained by plasma etching of SiO/sub 2/ using a silver island film as an etch mask. Silver particles are produced by angle evaporation. Raman enhancment for adsorbed p-nitrobenzoic acid is maximized by optimizing the deposition parameters, which results in a tenfold enhancement compared to island films and crossed-grating structures. Observation of signals from several polyaromatic molecules demonstrates that the surface provides strong Raman enhancement for a variety of adsorbates. 30 references, 3 figures, 2 tables.