A high‐throughput method for controlled hot‐spot fabrication in SERS‐active gold nanoparticle dimer arrays

Abstract

We present a high-throughput method for fabricating large arrays of surface-enhanced Raman scattering (SERS) active gold dimers. Using a large-area/low-cost nanopatterning method in conjunction with a meniscus force deposition technique, we were able to create large arrays of uniformly spaced nanoclusters comprising two 60-nm gold nanospheres. Raman measurements of a thiophenol monolayer deposited on smaller scale arrays of aligned dimers yielded enhancement factors as high as 10 9 . Polarization-controlled measurements show spectral peak heights to be 10-100 times smaller when the incident beam is polarized perpendicularly to the dimer axis, confirming that the measured enhancements arise from the 'hot spots' between the two nanospheres.

SERS Substrates by the Assembly of Silver Nanocubes: High-Throughput and Enhancement Reliability Considerations

“…In order to achieve high-throughput characterization, our focus is on methods that dictate apriori the sites on the substrate in which clusters will form. We present two methods based on (i) vertical deposition [27][28][29] and (ii) electrophoretic deposition [30] in patterned substrates. In both methods the SERS substrate preparation involves the synthesis of plasmonic nanoparticles as a colloidal solution followed by the templated assembly of the nanoparticles into discrete clusters.…”

“…Nanoparticles are deposited on the substrate as the air/liquid interface traverses the surface. When the surface of the substrate contains topographic steps, nanoparticle deposition is enhanced at the bottom of these steps [27][28][29]. In this work, topographic steps were generated by lithographic patterning and etching.…”

Surface-to-volume ratio controls the radiation of stratified plasmonic antennas

“…Additional features can be enabled by engineering the shape of nanoantennas, such as the broadband response of bowtie antennas, 9 the directionality of nano Yagi-Uda antennas, 10 and the ultralocalized and enhanced near-fields of gap antennas. [11][12][13][14][15][16][17][18][19][20][21][22][23] Several elements determine the field enhancement of a nanoantenna: strong photon-electron coupling at the metal surface, capacitive coupling at the disruption of the induced current path in the gap or at the end of the structure, and coupling to the surrounding environment. Although at optical frequencies the lateral dimensions of a nanoantenna are much smaller than the bulk penetration depth, the electric current density is not distributed uniformly, but rather it is higher at the surface of the structure.…”

Erratum: Fabrication of large-scale photonic phased array using a holographic lithography system

“…In the application regime of surface enhanced Raman spectroscopy (SERS) substrate, the periodic nanopatterns could be filled with Au or silver films or particles. 9 Because of the ability to support surface plasmonic polarization or localized surface plasmonic resonance, the nanopatterns can be used as a Raman substrate. Meanwhile, the ordering degree of nanopatterns can affect the amplitude of enhanced coupling electric field when adding an electric field on the array surface, thereby increasing the intensity of Raman scattering signals when the lattice surface is adhered by the molecules to be detected.…”