Abstract
Improving hot-spot intensity is a key issue in surface-enhanced Raman scattering (SERS). The bowtie nanoantenna (BNA) is an effective device used to concentrate light energy into a nanoscale volume and produce strong hot spots. Nanosphere lithography (NSL) is a large-area and low-cost technique to produce BNA arrays; however, the SERS activity of NSL-fabricated BNAs is limited. In this paper, we present a simple method to improve the SERS activity of conventional NSL-fabricated BNAs by modifying their geometry. The new configuration is termed “silver-coated elevated bowtie nanoantenna” (SCEBNA). SCEBNAs perform intensive near-field enhancement in the gap cavities owing to the integrated contribution of the “lightning rod” effect, resonance coupling, and the formation of the plasmonic Fabry–Pérot cavity. Experimental measurements and finite-difference time-domain simulations revealed that the hot-spot intensity and the substrate enhancement factor can be optimized by adjusting the silver thickness. The optimal sample has the capability of trace-amount detection with fine reproducibility.
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Feng, L., Ma, R., Wang, Y. et al. Silver-coated elevated bowtie nanoantenna arrays: Improving the near-field enhancement of gap cavities for highly active surface-enhanced Raman scattering. Nano Res. 8, 3715–3724 (2015). https://doi.org/10.1007/s12274-015-0871-2
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DOI: https://doi.org/10.1007/s12274-015-0871-2