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Title: Photoemission electron microscopy of localized surface plasmons in silver nanostructures at telecommunication wavelengths

We image the field enhancement at Ag nanostructures using femtosecond laser pulses with a center wavelength of 1.55 μm. Imaging is based on non-linear photoemission observed in a photoemission electron microscope (PEEM). The images are directly compared to ultra violet PEEM and scanning electron microscopy (SEM) imaging of the same structures. Further, we have carried out atomic scale scanning tunneling microscopy on the same type of Ag nanostructures and on the Au substrate. Measuring the photoelectron spectrum from individual Ag particles shows a larger contribution from higher order photoemission processes above the work function threshold than would be predicted by a fully perturbative model, consistent with recent results using shorter wavelengths. Investigating a wide selection of both Ag nanoparticles and nanowires, field enhancement is observed from 30% of the Ag nanoparticles and from none of the nanowires. No laser-induced damage is observed of the nanostructures neither during the PEEM experiments nor in subsequent SEM analysis. By direct comparison of SEM and PEEM images of the same nanostructures, we can conclude that the field enhancement is independent of the average nanostructure size and shape. Instead, we propose that the variations in observed field enhancement could originate from the wedge interface betweenmore » the substrate and particles electrically connected to the substrate.« less
Authors:
; ; ; ; ;  [1]
  1. Department of Physics, Lund University, P.O. Box 118, 22 100 Lund (Sweden)
Publication Date:
OSTI Identifier:
22413149
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 8; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; BIOMEDICAL RADIOGRAPHY; COMPARATIVE EVALUATIONS; EMISSION SPECTROSCOPY; INTERFACES; LASER RADIATION; NANOPARTICLES; NANOWIRES; PHOTOELECTRON SPECTROSCOPY; PHOTOEMISSION; PLASMONS; PULSED IRRADIATION; SCANNING ELECTRON MICROSCOPY; SCANNING TUNNELING MICROSCOPY; SILVER; SUBSTRATES; SURFACES; WORK FUNCTIONS