Metal-Film-Coated Silica Nanoparticle Monolayers for Application in Surface Enhanced Raman Scattering

Surface enhanced raman scattering is interested for a variety of applications, especially in determining the presence of substances at very low concentrations, at the level of ppm, that is obtained by amplifying the raman scattering signal of adsorbent particles on metal surfaces or nanostructures. In this paper, we report on surface enhanced raman scattering substrates based on metal-film-coated silica nanoparticle monolayer. The silica nanoparticles having the diameter of 196 nm are assembled into close-packaged monolayer on silicon substrate by spin coating technique. The gap among the silica nanoparticles is tuned by HF vapor etching. The investigations on reflectance characteristic and raman spectra show that close- and non-close-packaged monolayers on silicon substrate covered by a thin gold layer can be used as surface enhanced raman scattering substrates.