Safe fabrication of sharp gold tips for light emission in scanning tunnelling microscopy

M.G. Boyle, Lei Feng, Paul Dawson

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

Gold is the optimal tip metal for light emission in scanning tunnelling microscopy (LESTM) under ambient conditions. Sharp Au-tips of similar to 10nm radius were produced reliably using a safe, two-step etching method in 20% (w/w) CaCl2 solution. Previous CaCl2-based methods have tended to produce blunter tips, while other etching techniques that do produce sharp Au-tips, do so with the use of toxic or hazardous electrolytes. The tips are characterised using scanning electron microscopy and their efficacy in LESTM is evidenced by high-resolution, simultaneous topographic and photon mapping of Au(1 1 1)- and polycrystalline Au-surfaces. Spectra of the optical emission exhibit only one or two peaks with etched tips in contrast to the more complex spectra typical of cut tips; this feature, together with the highly symmetric geometry of the tips, facilitates a definitive analysis of the light emission process. (c) 2007 Elsevier B. V.. All rights reserved.
Original languageEnglish
Pages (from-to)558-566
Number of pages9
JournalUltramicroscopy
Volume108
Issue number6
DOIs
Publication statusPublished - May 2008

ASJC Scopus subject areas

  • Materials Science(all)
  • Instrumentation

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