Large Format Surface-Enhanced Raman Spectroscopy Substrate Optimized for Enhancement and Uniformity

Gratings have been widely investigated both theoretically and experimentally as surface-enhanced Raman spectroscopy (SERS) substrates, exhibiting, under appropriate circumstances, increased far-field extinctions and near-field intensities over those of an appropriately equivalent number of isolated particles. When the grating order transitions from evanescent to radiative, narrow resonance peaks are observed in the extinction spectrum whose properties can be manipulated by controlling the grating’s geometric parameters. Here we report the application of the architectural principles of grating fabrication using a square two-dimensional array of gold-coated nanostructures that achieves SERS enhancements of 107 uniformly over areas of square centimeters. The high-performance grating substrates were fabricated using commonly available foundry-based techniques that have been chosen for their applicability to large-scale wafer processing. Additionally, we restricted ourselves to a parametric regime that optimizes SERS performance in a repeatable and reproducible manner.