Substrate and laser power dependence of surface-enhanced Raman scattering from a silver oxide film

We report a method to improve the efficiency of surface-enhanced Raman scattering (SERS) from a silver oxide film. A 632.8 nm He-Ne laser beam was focused on silver oxide films deposited on different substrates (silica, TiO2, Si). We found that the substrate material greatly affected the SERS efficiency, and that silica substrate showed the highest efficiency among the materials measured. Scanning electron microscopy observations revealed that silver nanoparticles were generated within the focused laser spot. Computer simulations of the thermal profile based upon data from experimental observations were also carried out. It was found that the temperature of the silver oxide film differed greatly according to the substrate. We infer that substrates that allow higher silver-oxide-film temperatures to be attained are more suitable for efficient SERS.