Electron-energy loss spectroscopy in carbon nanotubes: low energy

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Electron-energy loss spectroscopy in carbon
nanotubes low energy

• Kamarás Katalin

MTA SZFKI
Thanks to Thomas Pichler, Dresden
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Plasmons
Plasmons are longitudinal oscillations of an
electron gas which can not be excited by the
electric field of light at normal incidence They
occur whenever and can be detected by the loss
of energy of an electron beam (EELS)
EELS measures the loss function
KK analysis
e1, e2
Results of the Dresden group are measured in
transmission on extremely thin (100 nm) samples
T. Pichler, M.Knupfer, M.S. Golden, J. Fink, A.G.
Rinzler, R.E. Smalley Phys. Rev. Lett. 80, 4729
(1998)
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Optical and energy-loss spectra
and
transitions
TO LO
electron collective resonance
The peak in EELS (the loss function ) occurs at
higher energy than the maximum in optical
absorption
X. Liu, T. Pichler, M. Knupfer, M.S. Golden, J.
Fink, H. Kataura, Y. Achiba Phys. Rev. B 66,
045411 (2002)
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VIS-UV spectra of nanotubes - plasmon peaks
X. Liu, T. Pichler, M. Knupfer, M.S. Golden, J.
Fink, H. Kataura, Y. Achiba Phys. Rev. B 66,
045411 (2002)
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Dispersion in EELS of nanotubes
and transitions show much broader
dispersion than transitions between van Hove
singularities
Polarization (TO, predicted) dispersive peaks
parallel to tube axis molecular peaks
perpendicular to tubes We know now that this is
not right due to the antenna effect!
T. Pichler, M.Knupfer, M.S. Golden, J.Fink, A.G.
Rinzler, R.E. Smalley Phys. Rev. Lett. 80, 4729
(1998)
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STEM (scanning transmission electron microscope)
/EELS measurements on individual samples
Spectra could be taken of bundles and individual
tubes, in penetrating mode (bulk plasmons) and
aloof mode (surface plasmons)
B.W. Reed, M. Sarikaya PRB 64, 195404 (2001)
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What next?
NEAR-FIELD MICROSCOPY AND NEAR-FIELD OPTICS by
Daniel Courjon (Université de Franche-Comté,
France)
Contents History of Near-field Optics
Non-radiating Sources and Non-propagating Fields
Evanescent Optics Theories and Modellings
Inverse Problem and Apparatus Function Criteria
of Quality, Noise and Artifacts Nano-collectors
and Nano-emitters Instrumentation Main
Near-field Microscope Configurations Near-field
Image Processing Applications of Near-field
Microscopy Appendix A Basis of Optics
Readership Optical researchers and engineers,
as well as graduates keen on peculiar optical
phenomena. 340pp Pub. date Mar 2003