title: Large area metal nanowire arrays with tunable sub-20 nm nanogaps.
abstract: We report a new top-down nanofabrication technology to realize large area metal nanowire (m-NW) arrays with tunable sub-20 nm separation nanogaps without the use of chemical etching or milling of the metal layer. The m-NW array nanofabrication technology is based on a self-regulating metal deposition process that is facilitated by closely spaced and isolated heterogeneous template surfaces that confine the metal deposition into two dimensions, and therefore, electrically isolated parallel arrays of m-NW can be realized with uniform and controllable nanogaps. Au-NW and Ag-NW arrays are presented with high-density ~10(5) NWs cm(-1), variable NW diameters down to ~50 nm, variable nanogaps down to ~5 nm, and very large nanogap length density ~1 km cm(-2). The m-NW arrays are designed and implemented as interdigitated nanoelectrodes for electrochemical applications and as plasmonic substrates where the coupled-mode localized surface plasmon resonance (LSPR) wavelength in the nanogaps between adjacent m-NW dimers can be precisely tuned to match any excitation source in the range from 500 to 1000 nm, thus providing optimal local electromagnetic field enhancement. A spatially averaged (n = 2500) surface-enhanced Raman scattering (SERS) analytical enhancement factor of (1.2 ± 0.1) × 10(7) is demonstrated from a benzenethiol monolayer chemisorbed on a Au-NW array substrate with LSPR wavelength matched to a He-Ne laser source.
authors: BIOS Lab on a Chip Group and MESA+ Institute for Nanotechnology, University of Twente, Enschede, The Netherlands.
authors: Loan
authors: L
authors: Le Thi Ngoc
authors: Mingliang
authors: M
authors: Jin
authors: Justyna
authors: J
authors: Wiedemair
authors: Albert
authors: A
authors: van den Berg
authors: Edwin T
authors: ET
authors: Carlen
mesh_terms: D004566:Electrodes; D008670:Metals / Q000737:chemistry*; D036103:Nanotechnology / Q000295:instrumentation*; D013499:Surface Properties
chemical_list: D008670:Metals