Lithography-free fabrication of scalable 3D nanopillars as ultrasensitive SERS substrates

Surface-enhanced Raman spectroscopy (SERS) detection of analyte molecules at ultra-low concentrations requires highly-efficient plasmonic nanostructures enabling a high hot-spot density. However, facile and cost-effective strategy toward large-area fabrication efficient with significant electromagnetic field enhancement remains great challenge. Further, SERS faces reliability issues the molecular fingerprint concentrations. This work shows one-step rapid technique utilizing glancing angle deposition for growing 3D nanopillars Ag or Au, which is facile, scalable cost-effective. The nanopillar substrates can reliably detect as low 10-18 M signal-to-noise ratio proven Cresyl violet, p-aminothiophenol Rhodamine 6G. ultra-high realized in conjunction formation density due to localized surface plasmons metal/air interface. A portable handheld spectrometer used evaluate potential application on-site diagnostics. It avoids need sophisticated tabletop instruments yet provides high-precision specificity outside specialized laboratories. show excellent limits 10−15 when tested spectrometer. uniqueness features hot-spots nanofabrication methods provide platform unravel diagnostics approaches.