15 August 1989 One And Two Photon Photoelectron Emission From Microscopically Rough Silver Surfaces
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Proceedings Volume 1056, Photochemistry in Thin Films; (1989) https://doi.org/10.1117/12.951625
Event: OE/LASE '89, 1989, Los Angeles, CA, United States
Abstract
Metallic silver is characterized in the near ultra-violet by a dielectric constant of small imaginary and small negative real components. This allows for intense, collective, conduction electron resonances at plane silver surfaces and for microscopic surface features. The consequent absorption and localization of electro-magnetic energy in such features is used to explain the giant enhancement observed for Raman scattering, second harmonic generation and other optical processes on roughened surfaces. For instance silver which has been vapour deposited onto low temperature substrates, so that there is little thermal annealing of the ballistically condensing metal, can show a 10 6 -fold enhancement in the Raman scattering of adsorbed molecules. We are interested in the photoemission of electrons from these metal films. Unfortunately the optical resonances occur at lower energies than that of the bulk plasmon at 3.8 eV, while clean silver has a photoelectric threshold above 4.1 eV; its precise value depending on the crystal face exposed. However the threshold is sensitive to adsorption and may be lowered a few tenths of an eV even by physisorbed gases. In this proceeding we report on photoemission at 3.7 eV from rough silver films. Others have studied electron emission into vacuum for plasmon region energies with the photoelectron threshold lowered by pyridine adsorption [1], by cesiation [1],[2], and also emission into electrolytic solution [3]. We have recently used two-photon non-linear photoemission with photon energies down to 2.1 eV as a probe for clean, high threshold surfaces [4].
© (1989) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Todd Stuckless, Todd Stuckless, Martin Moskovits, Martin Moskovits, } "One And Two Photon Photoelectron Emission From Microscopically Rough Silver Surfaces", Proc. SPIE 1056, Photochemistry in Thin Films, (15 August 1989); doi: 10.1117/12.951625; https://doi.org/10.1117/12.951625
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