Surface-enhanced Raman scattering sensing on black silicon

Authors

  • Gediminas Gervinskas,

    Corresponding author
    1. Centre for Micro-Photonics and Industrial Research Institute Swinburne, Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, Hawthorn, VIC, Australia
    2. The Australian National Fabrication Facility–ANFF, Victoria node, Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, Hawthorn, VIC, Australia
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  • Gediminas Seniutinas,

    1. Centre for Micro-Photonics and Industrial Research Institute Swinburne, Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, Hawthorn, VIC, Australia
    2. The Australian National Fabrication Facility–ANFF, Victoria node, Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, Hawthorn, VIC, Australia
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  • Jennifer S. Hartley,

    1. Centre for Micro-Photonics and Industrial Research Institute Swinburne, Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, Hawthorn, VIC, Australia
    2. The Australian National Fabrication Facility–ANFF, Victoria node, Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, Hawthorn, VIC, Australia
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  • Sasikaran Kandasamy,

    1. Melbourne Centre for Nanofabrication, Clayton, VIC, Australia
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  • Paul R. Stoddart,

    1. Centre for Micro-Photonics and Industrial Research Institute Swinburne, Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, Hawthorn, VIC, Australia
    2. The Australian National Fabrication Facility–ANFF, Victoria node, Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, Hawthorn, VIC, Australia
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  • Narges F. Fahim,

    1. Centre for Micro-Photonics and Industrial Research Institute Swinburne, Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, Hawthorn, VIC, Australia
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  • Saulius Juodkazis

    1. Centre for Micro-Photonics and Industrial Research Institute Swinburne, Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, Hawthorn, VIC, Australia
    2. The Australian National Fabrication Facility–ANFF, Victoria node, Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, Hawthorn, VIC, Australia
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Abstract

Reactive ion etching was used to fabricate black-Si over the entire surface area of 4-inch Si wafers. After 20 min of the plasma treatment, surface reflection well below 2% was achieved over the 300–1000 nm spectral range. The spikes of the black-Si substrates were coated by gold, resulting in an island film for surface-enhanced Raman scattering (SERS) sensing. A detection limit of 1 × 10−6 M (at count rate > 102 s−1 . mW−1) was achieved for rhodamine 6G in aqueous solution when drop cast onto a ∼ 100-nm-thick Au coating. The sensitivity increases for thicker coatings. A mixed mobile-on-immobile platform for SERS sensing is introduced by using dog-bone Au nanoparticles on the Au/black-Si substrate. The SERS intensity shows a non-linear dependence on the solid angle (numerical aperture of excitation/collection optics) for a thick gold coating that exhibits a 10 times higher enhancement. This shows promise for augmented sensitivity in SERS applications.

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