Metal-Dielectric-Metal Nanostructure With Broadband Near-perfect Light Absorption And Its Application As Surface Enhanced Raman Scattering Substrate

Metallic nanostructures which support Surface Plasmon Resonances(SPRs) can induce considerable novel physical effect of optics. Especially nowadays, since the further theoretical research and the rapid progress of the micromachining, Plasmonics which is developed based on the metallic nanostructures has shown great potential in the field of physics, optics, material science, biomedicine, information and energy science.In this paper, we study the optical property of the plasmonic complex structure of metallic nanoparticles/dielectric spacer/metallic layer and it’s application in SERS. We divide the paper into two parts as follows:Firstly, we fabricate the complex structure of metallic nanoparticles/dielectric spacer/metallic layer through combination of physical vapor deposition and low temperature annealing. After studying the influence of the Au thickness on top (the distribution of the Au particles on top) and the thickness of the dielectric spacer to the optical property of the complex structures, we find the best parameter combination to our complex structures which bring them the near-perfect absorption over 90% over 500-800nm.Secondly, we study the SERS contribution of the complex structures of metallic particles/dielectric spacer/metallic layer in details. We find the positive correlation between the SERS signal and it’s ability of absorption. While the near-perfect absorption range covers the pump location and the Raman scattering location, we get the greatest SERS signal which is at least one magnitude bigger than the metallic particles system under the same experimental conditions. Meanwhile, the broad range of the near-perfect absorption brings the flexible application to the complex structure for SERS, which can be used at multiple wavelengths, which has important meaning to broaden the application of the SERS.