Optimizing nanofabricated substrates for surface enhanced Raman scattering

Recently, Surface Enhanced Raman Scattering (SERS) has been used to record vibrational spectra from individual molecules adsorbed on colloidal silver particles. For specific particle dimensions an enormous enhancement, by a factor of 10(14), was achieved. In this work we intend to investigate the size and geometry dependence of the SERS effect on supported particles, by manufacturing artificial structures by modem nanofabrication techniques. Arrays of 100-200 nm silver particles of different shapes were prepared on a Si wafer by electron beam lithography, and were characterized by scanning electron microscopy. Preliminary Raman scattering experiments were performed with Rhodamin 6G (R6G) as a test molecule. Enhancement of the Raman signal was observed on all nanofabricated silver patterns, compared to the signals on a uniform silver film or on the (oxidized) Si surface. (C)1999 Acta Metallurgica Inc.