Surface-Enhanced Raman Microscopy Of Hemispherical Shells Stripped From Templates Of Anodized Aluminum

We report on the optical characterization of plasmonic metal nanostructures representing highly ordered interconnected hemispherical gold and silver shells that can be iteratively stripped from the same embossed templates (without template degradation) made from selectively etched anodized aluminum. By performing scanning high-resolution confocal Raman microscopy of p-aminothiophenol and Rhodamine 6G molecules homogeneously adsorbed to samples with different radii of shell curvature, we systematically investigate the applicability of the fabricated structures for surface-enhanced Raman spectroscopy and correlate the results with linear reflection spectroscopy. We trace the origin of strong Raman signal enhancements (average relative enhancement of up to similar to 120) to electromagnetic hot-spots located in sharp grooves and crevices at hemisphere shell junctions. Copyright (c) 2011 John Wiley & Sons, Ltd.