Volume 79 (2011) Issue 10 Pages 768-772
Plasmonic field localization is normally utilized on irregularly roughened surfaces or nanostructured surfaces of coinage metals. Although localized fields increase photon-molecule interactions, metal-molecule interactions become an uncontrollable variable because atomic surface features are not organized in such nanostructured metals. However, construction of sphere-plane nano-gaps on atomically defined metal surface enables us to manage metal-molecular interactions in addition to control of plasmonic resonance features. In SERS spectroscopy using this system, well-managed electromagnetic and chemical contributions provide detailed information on geometric and electronic structures of molecular adsorbates. Moreover, highly localized fields within the nano-gaps extend the range of SERS application to highly damping catalytic metal surfaces. In photo-energy conversion, incident photon to current conversion efficiency in porphyrin-based molecular monolayer system is largely increased by optical antenna effect of the nano-gaps.