Proposed Substrates for Reproducible Surface-Enhanced Raman Scattering Detection

    Authors

    W. F. Hu;S. L. Zou

    Comments

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    Abbreviated Journal Title

    J. Phys. Chem. C

    Keywords

    DISCRETE-DIPOLE APPROXIMATION; PLASMON RESONANCE; SILVER ELECTRODE; METAL NANOPARTICLES; GOLD NANOPARTICLES; ISLAND FILMS; SPECTROSCOPY; SERS; ARRAYS; SIZE; Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, ; Multidisciplinary

    Abstract

    The electromagnetic contribution to the surface-enhanced Raman scattering (SERS) derives from the distribution of electromagnetic "hot spots" around nanostructured metal surfaces. For an optimized SERS signal, analyte molecules need to be placed within the intense electric fields localized at these hot spots. Using numerical simulations, we demonstrate the possibility of creating controllable hot spots through proper engineering of the plasmonic modes supported by periodic arrays of nanoscale cavities in thin silver films. We investigate the tunability of surface plasmon resonance wavelength and local field enhancement by systematically varying the sample thickness, periodicity, and the nano cavity morphology. The gradual evolution of the absorption spectrum with these parameters helps reveal the relative contributions from surface plasmon polaritons propagating or localized at the metal surfaces. The calculations suggest that when the nanocavities are deep relative to the film thickness, there is strong confinement of surface plasmons which produces several orders of magnitude enhanced electric fields across the cavity bottom surfaces. Enhanced local electric field at the bottom of the cavity provides an efficient optical trap and the system can be used for reproducible SERS detection, especially for big nanometer sized biomolecules.

    Journal Title

    Journal of Physical Chemistry C

    Volume

    115

    Issue/Number

    11

    Publication Date

    1-1-2011

    Document Type

    Article

    Language

    English

    First Page

    4523

    Last Page

    4532

    WOS Identifier

    WOS:000288401200023

    ISSN

    1932-7447

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