Vertically oriented sub-10-nm plasmonic nanogap arrays

Hyungsoon Im, Kyle C. Bantz, Nathan C. Lindquist, Christy L. Haynes, Sang Hyun Oh

Research output: Contribution to journalArticle

303 Scopus citations

Abstract

Nanometric gaps in noble metals can harness surface plasmons, collective excitations of the conduction electrons, for extreme subwavelength localization of electromagnetic energy. Positioning molecules within such metallic nanogaps dramatically enhances light-matter interactions, increasing absorption, emission, and, most notably, surface-enhanced Raman scattering (SERS). However, the lack of reproducible high-throughput fabrication techniques with nanometric control over the gap size has limited practical applications. Here we show sub-10-nm metallic nanogap arrays with precise control of the gap's size, position, shape, and orientation. The vertically oriented plasmonic nanogaps are formed between two metal structures by a sacrificial layer of ultrathin alumina grown using atomic layer deposition. We show increasing local SERS enhancements of up to 109 as the nanogap size decreases to 5 nm. Because these sub-10-nm gaps can be fabricated at high densities using conventional optical lithography over an entire wafer, these results will have significant implications for spectroscopy and nanophotonics.

Original languageEnglish (US)
Pages (from-to)2231-2236
Number of pages6
JournalNano letters
Volume10
Issue number6
DOIs
StatePublished - Jun 9 2010

Keywords

  • Atomic layer deposition
  • Nanogap
  • Plasmonics
  • Surface plasmon
  • Surface-enhanced Raman scattering

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