Large-area, reproducible and sensitive plasmonic MIM substrates for surface-enhanced Raman scattering

Abstract

Vertically coupled plasmonic structure is of great interest for surface-enhanced Raman scattering (SERS). In this paper, a large-area reproducible SERS substrate is fabricated and demonstrated by a vertically coupled structure composed of Ag triangle arrays on Ag films separated by a nanometric dielectric layer. This metal-insulator-metal (MIM) nanostructure has broadband resonance covering both the laser excitation and Stokes frequencies. Thanks to the convenience of controlling the gap distance by thin dielectric film, the SERS substrate is optimized to yield the best enhancement. The SERS enhancement factor is estimated to be 5.8 × 10 for on-resonant pumping with a 532 nm laser. The uniformity and reproducibility of the SERS substrate are also demonstrated. Our results pave the way for rational design of sensitive SERS substrates and harmless exciting SERS signals.

Template‐Assisted Fabrication of Nanostructured Arrays for Sensing Applications

“…Wang et al. reported an Ag triangular particle array that exhibited an enhanced LSPR on the insulator‐coated Ag film . The SERS enhancement factor of this sample was estimated to be 5.8×10 6 upon excitation with a λ =532 nm laser.…”

“…The 0D nanostructured arrays, such as metallic particle arrays, are wildly employed as SERS substrates, for which strong light scattering and a large enhancement of the local electric fields exist . In comparison with 1D and 3D nanostructured arrays, the enhanced SERS sensitivity of the 0D nanostructure mainly occurs as a result of narrow gaps between neighboring particles.…”

“…This kind of convex‐rich 0D nanostructure is beneficial for plasmonic accumulation for an enhanced SERS signal. By using a colloidal monolayer template, Wang and co‐workers reported an Ag triangular array that was obtained through thermal evaporation of Ag on the template‐covered substrate . In the detection of R6G, the sample showed enhanced SERS sensitivity, compared with that of the Ag film (Figure a–c).…”

“…Reproduced with permission from Ref. , Copyright 2016, IOP Publishing. d,e) A Pd particle array and its conductance changes for various hydrogenated flows over the whole concentration range from 2 to 100 % H 2 in N 2 .…”

Multifunctional Skin‐Inspired Flexible Sensor Systems for Wearable Electronics

“…Particularly, SERS has attracted intensive research attentions due to its capability to provide fingerprint information of analytes with narrow spectral peaks . To achieve high‐performance SERS substrates, it is crucial to deliberately engineer uniform large‐scale plasmonic nanostructures with high‐density of “hot‐spots,” allowing the generation of enhanced electric fields as large as possible . Huge efforts, in the past decades, thus have been dedicated to exploiting versatile SERS platforms by rational chemical syntheses or advanced lithographic routes in aqueous solutions or on rigid substrates …”