Tip-Enhanced Raman Nanographs of Plasmonic Silver Nanoparticles

Tip-enhanced Raman scattering (TERS) from plasmonic silver nanoparticles traces spatial variations in optical fields defined by the interaction of the plasmonic probe with nanoscale topographic features that are characteristic of crystalline particles. This is demonstrated through correlated atomic force microscopy (AFM)–TERS imaging of ∼100 nm silver nanoparticles coated with 4-mercaptobenzonitrile (MBN) molecules. In effect, the recorded spectral images are sensitive to the 3D topographic makeup of the particle and broadcast local optical fields that vary over a few nanometers of length scale.