Gold nanoparticle cluster arrays for advanced optical sensing: an AFM study

We studied a strategy for developing reproducible and stable 2D arrays of fractal micrometric gold nanoparticles arranged on silicon substrates. The combined use of electron beam lithography and molecular functionalization allowed us to finely control the shape of nanoparticle assemblies in designed areas. Atomic force microscopy measurements confirmed the regularity in spacing and size (i.e. area and layer number) of the obtained aggregates. Preliminary microRaman space resolved measurements were undertaken on a 100x100 μm2 2D array made up of 10 μm-spaced, 1 μm2 large clusters. The high surface enhanced Raman signal measured on the structure allowed us to point out a full correspondence in the periodical spacing both optically and topographically achieved. This may represent the basis to realize intriguing platforms for nano-optical investigation and towards an efficient high-sensitive multiplex sensing.