Broadband Nanoscale Surface-Enhanced Raman Spectroscopy by Multiresonant Nanolaminate Plasmonic Nanocavities on Vertical Nanopillars
Meitong Nie, Yuming Zhao, Wonil Nam, Junyeob Song, Wenqi Zhu, Henri Lezec, Amit Agrawal, Wei Zhou
Surface-enhanced Raman spectroscopy (SERS) has become a sensitive detection technique for biochemical analysis. Despite significant research efforts, most SERS substrates consisting of single-resonant plasmonic nanostructures on the planar surface suffer from limitations of narrowband SERS operation and unoptimized nano-bio interface with living cells. Here, we report that nanolaminate plasmonic nanocavities on three-dimensional (3D) vertical nanopillar arrays can support a broadband SERS operation with large enhancement factors (> 106) under laser excitations at 532 nm, 633 nm, and 785 nm. The multi-band Raman mapping measurements show that nanolaminate plasmonic nanocavities on vertical nanopillar arrays exhibit broadband uniform SERS performance with diffraction-limited resolution at a single nanopillar footprint. By selective exposure of embedded plasmonic hotspots in individual metal-insulator-metal (MIM) nanogaps, we demonstrate nanoscale broadband SERS operation at the single MIM nanocavity level with visible and near-infrared (vis-NIR) excitations. Numerical studies reveal that nanolaminate plasmonic nanocavities on vertical nanopillars can support multiple hybridized plasmonic modes to concentrate optical fields across a broadband wavelength range from 500 nm to 900 nm at the nanoscale.
, Zhao, Y.
, Nam, W.
, Song, J.
, Zhu, W.
, Lezec, H.
, Agrawal, A.
and Zhou, W.
Broadband Nanoscale Surface-Enhanced Raman Spectroscopy by Multiresonant Nanolaminate Plasmonic Nanocavities on Vertical Nanopillars, Advanced Functional Materials, [online], https://doi.org/10.1002/adfm.202202231, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=934309
(Accessed October 3, 2022)