Ultrasmall Plasmonic Single Nanoparticle Light Source Driven by a Graphene Tunnel Junction

Seon Namgung, Daniel A. Mohr, Daehan Yoo, Palash Bharadwaj, Steven J. Koester, Sang Hyun Oh

Research output: Contribution to journalArticle

9 Scopus citations


Metal nanoparticles that can couple light into tightly confined surface plasmons bridge the size mismatch between the wavelength of light and nanostructures are one of the smallest building blocks of nano-optics. However, plasmonic nanoparticles have been primarily studied to concentrate or scatter incident light as an ultrasmall antenna, while studies of their intrinsic plasmonic light emission properties have been limited. Although light emission from plasmonic structures can be achieved by inelastic electron tunneling, this strategy cannot easily be applied to isolated single nanoparticles due to the difficulty in making electrical connections without disrupting the particle plasmon mode. Here, we solve this problem by placing gold nanoparticles on a graphene tunnel junction. The monolayer graphene provides a transparent counter electrode for tunneling while preserving the ultrasmall footprint and plasmonic mode of nanoparticle. The tunneling electrons excite the plasmonic mode, followed by radiative decay of the plasmon. We also demonstrate that a dielectric overlayer atop the graphene tunnel junction can be used to tune the light emission. We show the simplicity and scalability of this approach by achieving electroluminescence from single nanoparticles without bulky contacts as well as millimeter-sized arrays of nanoparticles.

Original languageEnglish (US)
Pages (from-to)2780-2788
Number of pages9
JournalACS nano
Issue number3
StatePublished - Mar 27 2018

How much support was provided by MRSEC?

  • Shared

Reporting period for MRSEC

  • Period 5

PubMed: MeSH publication types

  • Journal Article
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

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  • Projects

    University of Minnesota MRSEC (DMR-1420013)

    Lodge, T. P.


    Project: Research project

    MRSEC SEED Projects

    11/1/14 → …

    Project: Research project

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