Surface enhanced Raman scattering from a hierarchical substrate of micro/nanostructured silver

We prepared ordered, two-dimensional arrays of patterns with silver nanoparticles immobilized on patterned self-assembled monolayers (SAMs) of alkanethiolates on gold, which were used as substrates for surface enhanced Raman scattering (SERS). Using contact-mode atomic force microscopy, we have characterized the formation and structure of such silver pattern assemblies on a microcontact-printed SAM patterned surface. SERS spectra and surface enhanced Raman mapping (SERM) of 4-pyridinethiol SAMs on this novel SERS-active substrate were also investigated. Different SERS activities were observed on the surface of the hierarchical micro/nanostructure. The enhancement factor was studied in detail and the electromagnetic enhancement mechanism was used to explain the SERS effect. Copyright (C) 2006 John Wiley & Sons, Ltd.