Ultrahigh vacuum tip-enhanced raman spectroscopy with picosecond excitation

Eric A. Pozzi, Matthew D. Sonntag, Nan Jiang, Naihao Chiang, Tamar Seideman, Mark C. Hersam, Richard P. Van Duyne*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

33 Scopus citations

Abstract

Tip-enhanced Raman spectroscopy (TERS) provides chemical information about adsorbates with nanoscale spatial resolution, but developments are still required in order to incorporate ultrafast temporal resolution. In this Letter, we demonstrate that a reliable TER signal of rhodamine 6G (R6G) using picosecond (ps)-pulsed excitation can be obtained in ultrahigh vacuum (UHV). In contrast to our previous observation of irreversible signal loss in ambient TERS (Klingsporn, J. M.; Sonntag, M. D.; Seideman, T.; Van Duyne, R. P. J. Phys. Chem. Lett. 2014, 5, 106-110), we demonstrate that the UHV environment decreases irreversible signal degradation. As a complement to the TERS experiments, we examined the rate of surface-enhanced Raman (SER) signal decay under picosecond irradiation and found that it is also slowed in UHV compared to that in ambient. Signal decay kinetics suggest that the predominant mechanism responsible for signal loss in ps SERS of R6G is surface diffusion. Both diffusive and reactive phenomena can lead to pulsed excitation TER signal loss, and a UHV environment is advantageous in either scenario.

Original languageEnglish (US)
Pages (from-to)2657-2661
Number of pages5
JournalJournal of Physical Chemistry Letters
Volume5
Issue number15
DOIs
StatePublished - Aug 7 2014

Keywords

  • kinetics
  • plasmonics
  • tip-enhanced Raman spectroscopy
  • ultrafast spectroscopy
  • ultrahigh vacuum

ASJC Scopus subject areas

  • Materials Science(all)
  • Physical and Theoretical Chemistry

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