title: Plasmonic nanopillar arrays for large-area, high-enhancement surface-enhanced Raman scattering sensors.
abstract: Efforts to create reproducible surface-enhanced Raman scattering (SERS)-based chemical and biological sensors has been hindered by difficulties in fabricating large-area SERS-active substrates with a uniform, reproducible SERS response that still provides sufficient enhancement for easy detection. Here we report on periodic arrays of Au-capped, vertically aligned silicon nanopillars that are embedded in a Au plane upon a Si substrate. We illustrate that these arrays are ideal for use as SERS sensor templates, in that they provide large, uniform and reproducible average enhancement factors up to ∼1.2 × 10(8) over the structure surface area. We discuss the impact of the overall geometry of the structures upon the SERS response at 532, 633, and 785 nm incident laser wavelengths. Calculations of the electromagnetic field distributions and intensities within such structures were performed and both the wavelength dependence of the predicted SERS response and the field distribution within the nanopillar structure are discussed and support the experimental results we report.
authors.affiliation: U.S. Naval Research Laboratory, 4555 Overlook Avenue, S.W., Washington, D.C. 20375, United States. joshua.caldwell@nrl.navy.mil
authors.forename: Joshua D
authors.initials: JD
authors.lastname: Caldwell
authors.forename: Orest
authors.initials: O
authors.lastname: Glembocki
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Bezares
authors.forename: Nabil D
authors.initials: ND
authors.lastname: Bassim
authors.forename: Ronald W
authors.initials: RW
authors.lastname: Rendell
authors.forename: Mariya
authors.initials: M
authors.lastname: Feygelson
authors.forename: Maraizu
authors.initials: M
authors.lastname: Ukaegbu
authors.forename: Richard
authors.initials: R
authors.lastname: Kasica
authors.forename: Loretta
authors.initials: L
authors.lastname: Shirey
authors.forename: Charles
authors.initials: C
authors.lastname: Hosten
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D008027:Light; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000295:instrumentation*; D010316:Particle Size; D012542:Scattering, Radiation; D020349:Surface Plasmon Resonance / Q000295:instrumentation*; D014159:Transducers