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10/04/09 - UMH - séminaire Prof. Krasheninnikov - Irradiation of carbon nanomaterials with electrons and ions: from defects to self-organization

Ajouté le Mercredi 11 Mars 2009

Irradiation of carbon nanomaterials with electrons and ions: from

defects to self-organization


Prof. Arkady Krasheninnikov

Materials Physics Division, Université d’Helsinki Finlande

Vendredi 10 Avril 2009, 10h30

The irradiation of solids with energetic particles such as electrons
or ions is associated with disorder, normally an undesirable
phenomenon. However, recent experiments on bombardment of carbon
nanostructures with energetic particles demonstrate that irradiation
can have beneficial effects and that electron or ion beams may serve
as tools to change the morphology and tailor mechanical, electronic
and even magnetic properties of nanostructured carbon systems, and
first of all, carbon nanotubes. We systematically study irradiation
effects [1] in carbon nanotubes and other forms of nano-structured
carbon. By employing various atomistic models ranging from empirical
potentials [2] to time-dependent density functional theory [3] we
simulate collisions of energetic particles with carbon nanostructures,
and calculate the properties of the irradiated systems. In my
presentation, I briefly review the recent progress in our
understanding of ionirradiation-induced phenomena in nano-structured
carbon and compare the simulation results to the experimental data. I
dwell on the "beneficial" role of defects and impurities in nanotubes
and related systems. Finally, I will present the results of
simulations of irradiationinduced pressure build-up inside nanotubes
[4] and onions [5] encapsulated with metals. Electron irradiation of
such composite systems in the transmission electron microscope gives
rise to contraction of nanotube shells and thus to pressure in the
encapsulate. In such systems, irradiation-stimulated pressure can be
as high as 40 GPa, which makes it possible to study phase
transformations at the nanoscale with high spatial resolution.

[1] A.V Krasheninnikov, F. Banhart, Nature Materials, 6 (2007) 723.
[2] A. Tolvanen, A.V. Krasheninnikov, and K. Nordlund, Appl. Phys. Lett. 91
(2007) 173109.
[3] A.V KrasheninnikovY. Miyamoto, and D. Tomanek, Phys. Rev. Lett., 99(2007)
016104
[4] L. Sun, F. Banhart, A.V Krasheninnikov, J.A. Rodriguez-Manzo, M. Terrones,
and P.M. Ajayan, Science 312 (2006) 1199.
[5] L. Sun, A.V. Krasheninnikov, T. Ahlgren, K. Nordlund, and F. Banhart,
Phys. Rev. Lett., 101 (2008) 156101.


Ce séminaire se déroulera à l’amphithéâtre Vésale 020, situé sur le
Campus des Sciences et de la Médecine de l’Université de Mons. Un plan
d’accès est disponible sur le site de l’Université
(http://www.umh.ac.be/plan_Mb.html).

Informations complémentaires :
Prof. Rony Snyders Académie Universitaire Wallonie-Bruxelles
Laboratoire de Chimie Inorganique et Analytique, LCIA

Université de Mons-Hainaut, UMH
1, Avenue Copernic, 7000 Mons, Belgium
Tel: 32(0)65373855, Fax: 32(0)65373841
http://w3.umh.ac.be/~chinorg/
http://www.umh.ac.be/
http://www.materia-nova.com/

Dernière mise à jour par EDT MAIN Mercredi 11 Mars 2009