SERS amplification by ultra-dense plasmonic arrays on self-organized PDMS templates

High density gold nanostructures are grown by thermal deposition on flat and nanostructured polymeric templates by exploiting the extraordinarily low wettability of Au on polydimethylsiloxane (PDMS). Undulated PDMS templates are fabricated by replica molding process (REM) on “masters” prepared by defocused Ion Beam Sputtering (IBS). Closely packed and laterally disconnected Au nanostructures are grown at grazing incidence on the PDMS replica templates exploiting the shadowing instability. The peculiar nanocluster morphology determines a Localized Surface Plasmon Resonances (LSPR) which is tunable in the visible range by varying light polarization and metal dose. All samples exhibit a strong increase of the Surface Enhanced Raman Scattering (SERS) intensity with amplification factors exceeding 103.