Engineering Hot Spots on Plasmonic Nanopillar Arrays for SERS: A Review

Nanopillar arrays have provided unique optical properties due to their multi-dimensional architectures with large surface area. Recently, surface enhanced Raman spectroscopy (SERS) has taken full benefits of nanopillar arrays for highly sensitive chemical and biosensing. This article gives an overview of hot spot engineering on nanopillar arrays for SERS. Nanopillar arrays are very beneficial for providing high density plasmonic nanostructures, which induce the oscillation of free electrons to create highly localized electric fields, i.e., electromagnetic hot spots, for highly intense SERS detection. The diverse methods have successfully demonstrated the nanofabrication of hotspot-rich nanopillar arrays on silicon or glass substrates. Tailoring hot spots enables ultrasensitive detection of biomolecules at low concentrations and even allows single-molecule level detections. This review overviews the nanofabrication methods for nanopillar array construction, the design strategies for electromagnetic hot spot generation on nanopillar arrays, and their SERS applications.