Sensitive and reproducible surface-enhanced raman spectroscopy (SERS) with arrays of dimer-nanopillars

Abstract

It is challenge for most metallic nanostructures to produce both reproducible and high sensitive SERS enhancement, which hinder practical applications of SERS technology. In this work, we report that gold-coated silicon (Au@Si) dimer-nanopillar arrays can be used as SERS substrates with both high-sensitivity and reproducibility. The substrates consist of dimer-nanopillars with height of 480 nm and gaps of 8−10 nm fabricated with electron-beam lithography and followed plasma etching. The dimer-nanopillars have demonstrated SERS enhancement factors (EFs) of 4.3−8.0 × 109 with SERS signals relative standard deviation (RSD) of 3.2−5.6 % (reproducibility). The EFs are 2–3 orders of magnitude higher in comparison with that of other types of ordered nanostructures and are comparable with those of chemically synthesized nanoparticle aggregates. Meanwhile, the reproducibility is among the best ever reported. The dimer-nanopillar arrays were applied for detection of component of rapeseed oil. Cooked and uncooked oil can be clearly identified from the SERS spectra. Our study demonstrated that the dimer-nanopillars are promising to develop highly enhancing and reproducible SERS substrates for SERS sensing applications.