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 journalArticlepeer-review

26 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

Bibliographical note

Funding Information:
This work was supported by grants from the National Science Foundation (NSF Grant No. ECCS 1610333 to S.N., D.Y., S.-H.O.), Seagate Technology (D.A.M., S.-H.O.). This work was also supported in part by the Air Force Office of Scientific Research under Award No. FA9550-14-1-0277 (S.N., S.J.K.) and a startup grant from Rice University (P.B.). Device fabrication was performed at the Minnesota Nanofabrication Center at the University of Minnesota, which receives partial support from the NSF through the National Nanotechnology Coordinated Infrastructure (NNCI). Portions of this work were also carried out in the University of Minnesota Characterization Facility, which receives capital equipment funding from the NSF through the MRSEC program under Award No. DMR-1420013.

Publisher Copyright:
© 2018 American Chemical Society.

MRSEC Support

  • Shared

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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