Large-area, reproducible and sensitive plasmonic MIM substrates for surface-enhanced Raman scattering.
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 × 106for 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.
Department of Optics and Optical Engineering & Anhui Key Laboratory of Optoelectronic Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China. College of Physics and Electronics Information, Anhui Normal University, Wuhu, Anhui 241000, People's Republic of China.
Kuanguo
K
Li
Yong
Y
Wang
Kang
K
Jiang
Yuan
Y
Ren
Yanqiu
Y
Dai
Yonghua
Y
Lu
Pei
P
Wang