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

Journal Article · Sat Feb 28 04:00:00 EST 2015 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4913310· OSTI ID:22413149

Mårsell, Erik; Larsen, Esben W.; Arnold, Cord L.; Xu, Hongxing; Mauritsson, Johan; Mikkelsen, Anders ^[1]

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1. Department of Physics, Lund University, P.O. Box 118, 22 100 Lund (Sweden)

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 between the substrate and particles electrically connected to the substrate.

• OSTI ID: 22413149
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 8 Vol. 117; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

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