Electromagnetic Field Enhancement in the Multilayer of Metallic Nanomesh Films: Synthesis and Application as Surface-Enhanced Raman Scattering Substrates

We have fabricated uniform, large-area, and two-dimensional arrays of gold (and silver) nanomesh structures via metal sputtering on an anodic aluminum template. We studied the localized surface plasmon resonance originating from the edges of nanopores in the nanomesh structure. The resulting metal nanomeshes exhibited strong surface-enhanced Raman scattering (SERS) signals, and the measured SERS response was highly uniform throughout the whole surface area. The localized surface plasmon enhancement at the edge of the nanopores in the metal nanomesh structures is believed to be responsible for the strong SERS response. Also, we fabricated Au/Ag multilayer nanomesh structures with different stacking orders to further enhance the SERS response by utilizing the junctions between Ag and Au nanomesh films. The irradiated light can effectively penetrate deep into the multilayer metal nanomesh films through the nanopores. The SERS enhancement is maximized when the nanomesh structures are stacked alternately with Au and Ag nanomeshes as compared to homogeneous Au/Au or Ag/Ag stacked nanomesh films.