Density effect of gold nanodisks on the SERS intensity for a highly sensitive detection of chemical molecules

Surface-enhanced Raman scattering (SERS) is a sensitive and widely used as spectroscopic technique for chemical and biological structure analysis. One of the keys to increase the sensitivity of SERS sensors is to use nanoparticles/nanostructures. Here, we report on the density effect of gold nanodisks on SERS intensity for a highly sensitive detection of chemical molecules. Various densities of gold nanodisks with a height of 30 nm on gold/glass substrate were fabricated by electron beam lithography in order to have a good uniformity and reproducibility. The evolution of the enhancement factor (EF) with nanodisk density was quantified and compared to numerical calculations. An EF as high as $$2.6 \times 10⁷$$ was measured for the nanodisk with a diameter of 110 nm and a periodicity of 150 nm which corresponds to the highest density (42.2 %).