Gallium plasmonics: deep subwavelength spectroscopic imaging of single and interacting gallium nanoparticles.


Journal Article

Gallium has recently been demonstrated as a phase-change plasmonic material offering UV tunability, facile synthesis, and a remarkable stability due to its thin, self-terminating native oxide. However, the dense irregular nanoparticle (NP) ensembles fabricated by molecular-beam epitaxy make optical measurements of individual particles challenging. Here we employ hyperspectral cathodoluminescence (CL) microscopy to characterize the response of single Ga NPs of various sizes within an irregular ensemble by spatially and spectrally resolving both in-plane and out-of-plane plasmonic modes. These modes, which include hybridized dipolar and higher-order terms due to phase retardation and substrate interactions, are correlated with finite difference time domain (FDTD) electrodynamics calculations that consider the Ga NP contact angle, substrate, and native Ga/Si surface oxidation. This study experimentally confirms previous theoretical predictions of plasmonic size-tunability in single Ga NPs and demonstrates that the plasmonic modes of interacting Ga nanoparticles can hybridize to produce strong hot spots in the ultraviolet. The controlled, robust UV plasmonic resonances of gallium nanoparticles are applicable to energy- and phase-specific applications such as optical memory, environmental remediation, and simultaneous fluorescence and surface-enhanced Raman spectroscopies.

Full Text

Duke Authors

Cited Authors

  • Knight, MW; Coenen, T; Yang, Y; Brenny, BJM; Losurdo, M; Brown, AS; Everitt, HO; Polman, A

Published Date

  • February 6, 2015

Published In

Volume / Issue

  • 9 / 2

Start / End Page

  • 2049 - 2060

PubMed ID

  • 25629392

Pubmed Central ID

  • 25629392

Electronic International Standard Serial Number (EISSN)

  • 1936-086X

International Standard Serial Number (ISSN)

  • 1936-0851

Digital Object Identifier (DOI)

  • 10.1021/nn5072254


  • eng