Large area metal nanowire arrays with tunable sub-20nm nanogaps

Loan Le Thi Ngoc, Mingliang Jin, Justyna Wiedemair, Albert van den Berg, Edwin Carlen

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    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.
    Original languageUndefined
    Pages (from-to)5223-5234
    Number of pages12
    JournalACS nano
    Volume7
    Issue number6
    DOIs
    Publication statusPublished - 25 Jun 2013

    Keywords

    • EWI-23632
    • METIS-297029
    • Metal nanowire arrays . top-down nanofabrication . nanoelectrodes . metal nanograting . plasmonic substrates
    • IR-86819

    Cite this

    Le Thi Ngoc, L., Jin, M., Wiedemair, J., van den Berg, A., & Carlen, E. (2013). Large area metal nanowire arrays with tunable sub-20nm nanogaps. ACS nano, 7(6), 5223-5234. https://doi.org/10.1021/nn4009559