Tip-enhanced spectroscopy from ordered silver nanoparticle arrays

ORAL

Abstract

I will report on recent efforts from our group to develop new methods for enhanced spectroscopy from metal nanoparticle arrays. Triangular-shaped silver nanoparticles (20 -- 200 nm) fabricated via nanosphere lithography have shown dramatic enhancement (10$^{6}$ -- 10$^{10})$ of the resonance Raman spectrum of R6G, which was attributed to the shape of the Ag triangle.\footnote{ J. Schmidt, S. Cross, S. Buratto J. Chem. Phys., \textbf{121}, 10657 (2004).} In addition to the large surface-enhanced resonance Raman spectroscopy (SERRS) enhancement we have also observed enhanced luminescence from the Ag nanoparticle films. In order to further understand the shape dependence of the electric-field enhancement we have used near-field scanning optical microscopy (NSOM) to map both the SERRS and luminescence for a single 200nm Ag nanotriangle. The enahancement is largest for the apex of the triangle or near sharp points. In addition, I will discuss the progress in tip-enhanced SERS (TE-SERS) from these same nanoparticle arrays. In TE-SERS the electric field enhancement is due to the large coupling between the metal tip and the Ag nanoparticle and can be mapped and quantified.

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Authors

  • Erin Orazem

  • David Bussian

    • University of California, Santa Barbara

  • Sarah Cross

    • University of Califronia, Los Angeles

  • Jason Schmidt

    • The Clorox Company

  • Melissa Summers

    • Stanford University

  • Steve Buratto

    • Department of Chemistry \& Biochemistry, University of California, Santa Barbara, Santa Barbara, CA 93106
    • University of California, Santa Barbara
    • UCSB