Two-photon photoemission from silver nanoparticles on thin alumina films: Role of plasmon excitation

Florian Evers, Christoph Rakete, Kazuo Watanabe, Dietrich Menzel, Hans Joachim Freund

Research output: Contribution to journalArticlepeer-review

36 Scopus citations

Abstract

Two-photon photoemission (2PPE) from silver nanoparticles on a thin Al 2O3 film on NiAl(1 1 0) has been investigated using femtosecond lasers. The 2PPE spectra show a feature similar to the surface state of Ag(1 1 1). The total 2PPE yield possesses a maximum at about 3.6 eV which corresponds to the surface plasmon resonance of the silver particles. For particle sizes of about 10 nm an enhancement by a factor 450 compared to Ag(1 1 1) is found. Up to this diameter the photoemission yield increases but levels off for larger sizes due to interactions between the particles. It is inferred that the 2PPE process is a direct transition via a virtual state, and that the enhanced 2PPE yield results from the enhancement of the electromagnetic field at the surface of nanoparticles.

Original languageEnglish
Pages (from-to)43-48
Number of pages6
JournalSurface Science
Volume593
Issue number1-3
DOIs
StatePublished - 20 Nov 2005

Keywords

  • Cluster
  • Photoelectron spectroscopy
  • Plasmon
  • Silver
  • Surface photochemistry

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