Laboratoire Francis PERRIN
URA CNRS-CEA 2453
This website is no more mainteined. See LIDYL or NIMBE
The GOUTTELIUM setup : an IR spectroscopy in a cold environment
Last Update: 29 July 2014

Etude du photorécepteur "Photoactive Yellow Protein" par dichroïsme circulaire femtoseconde
Last Update: 21 February 2016

L'interaction médicament-protéine étudié par spectroscopie de fluorescence résolue en temps
Last Update: 9 December 2013

"Cœur silicium - coquille carbone" pour batteries Li-Ion
Last Update: 6 October 2015

Dynamic of peptids in gas phase and photostability of proteins
Last Update: 21 May 2013

A method to observe the complete vibrational spectrum of ionized molecules
Last Update: 21 May 2013

The strength of the NHamide---Smethionine revealed by spectroscopy of small peptides
Last Update: 21 May 2013

Imagerie photochimique du champ proche optique de nanocubes d’or
Last Update: 15 March 2012

Des tapis de nanotubes alignés, en grande surface !
Last Update: 31 January 2012

Nouvelles lumières sur l’interaction entre les rayons UVA et l’ADN
Last Update: 3 February 2014

Synergy btetween experiment and theory for the simulation of protein folding
Last Update: 21 September 2010

Un nouveau composé aux propriétés intéressantes d'absorption optique dans le domaine visible : TiO
Last Update: 17 June 2010

Synthèse de nanotubes marqués au carbone 14 pour des études de biodistribution
Last Update: 13 January 2011

A surprising dynamic of cluster fragmentation
Last Update: 13 November 2007

Chirality and folding of peptide chains
Last Update: 23 March 2007

Recent results in physicochemistry with the very new laser PLFA
Last Update: 16 March 2007

Effets coopératifs dans l'absorption du rayonnement UV par les bases de l'ADN
Last Update: 3 February 2014

Repliement de chaînes peptides en détente supersonique
Last Update: 3 February 2014

Formation of carbon nanotube multi-layers and identification of their growth mode
M. Pinault1, M. Mayne-L’Hermite1, C. Reynaudpage1 ,H. Khodja2 ,V. Pichot3 , P. Launois3

1CEA Saclay - DSM/DRECAM/Service des Photons, Atomes et Molécules - Laboratoire Francis Perrin
2CEA Saclay - DSM/DRECAM/Laboratoire Pierre Sue
3Laboratoire de Physique des Solides, CNRS UMR 8502, Univ. Paris Sud, 91405 Orsay

 


Since their discovery by Ijima in 1991, carbon nanotubes are always also attractive by their structure and their resulting remarkable properties. Their mechanism of growth itself does not cease intriguing the scientific community. Generally their formation takes place on a substrate by reaction between a carbonaceous molecule and a catalytic nanoparticule (Iron, Nickel, or Cobalt) at an adequate temperature. Base-growth, i.e. the nanotube grows up above the particle that remains on the substrate, as well as top-growth where the particle remains in top of the growing nanotube are observed. But very little direct experimental evidences exist about the advance of carbon during these processes.

A method of synthesis using a toluene and ferrocene aerosol which reacts on the hot substrate has been developed in Saclay. Clean and perfectly aligned carpets of multi-wall carbon nanotubes are obtained. The growth rate is important, and the thickness of the carpet may reach up to a few millimeters. The study of the earliest growth instants reveals the initial formation of catalytic nanoparticles on the substrate, followed by the growth of the nanotubes "from the base". However, some questions remain: how the growth can continue "from the base" when a carpet of several millimeters is formed ? What is the path of the carbon atoms?

 

To better understand how the growth continues, the team had the idea to make successive syntheses, by stopping the process and continuing it under identical or modified conditions. This allowed pointing out a remarkable phenomenon: the growth always starts again from the substrate by raising if necessary the previously grown carpets of nanotubes. This is illustrated by the left-hand picture where successive growths with decreasing durations were performed. The height of the carpet being proportional to the duration of the sequence, it is easy to attribute the top layer to the first synthesis and the bottom one to the very last.

Thus, that proves that the precursors diffuse through all the height of the pre-existent carpet to react only on the substrate. Moreover, this reaction takes place only if the metal precursor is present. In its absence, only a fine layer of amorphous carbon is formed, under which the nanotubes grow again as soon as the metal precursor is reintroduced. It is even possible to grow a new carpet under another which was left and the sample stored outside the engine.

 
Successive growth of nanotube layers. The last formed layer is in contact with t

Successive growth of nanotube layers. The last formed layer is in contact with the substrate. The most thick layer (on top) is the first formed layer.
The ultimate growth was made with a carbon 13 enriched vapour. The evolution of

The ultimate growth was made with a carbon 13 enriched vapour. The evolution of the C13 concentration shows that the growth occurs at the contact to the substrate after diffusion of the carbon atoms across the existing nanotube layers.

Lastly, the sequential use of two solutions, the second being 13C enriched, shows definitively that the carbon atoms diffuse well through all the preexistent carpet of nanotubes or in growth and are introduced only into nanotubes in contact with the catalytic particle on the substrate. This result was obtained by carrying out a cartography of the samples (see the the right-hand image) by means of the nuclear micro-probe of Saclay. Thus, the mechanisms governing the growth of the nanotube layers are well-identified together with the process to form controlled multi-layer of aligned carbon nanotubes that opens the way to multiple applications.

Thus, not only the mechanisms governing the growth of aligned nanotubes were greatly clarified, but we have now the way to control the growth of multilayers of aligned carbon nanotubes, opening the way to multiple applications.

14-11-2005

 

References :

[1] "Growth of multiwalled carbon nanotubes during the initial stages of aerosol-assisted CCVD" M. Pinault, M. Mayne-L’Hermite, C. Reynaud, V. Pichot, P. Launois and D. Ballutaud, Carbon 43, 2968, (2005)

[2] “Evidence of sequential lift in growth of aligned multi-walled carbon nanotube multilayers” M. Pinault, V. Pichot, H. Khodja, P. Launois, C. Reynaud and M. Mayne-L’Hermite, Nano Lett. 5 (12), 2394, (2005).

 

Participation d'un état de Rydberg à la redistribution ultrarapide de l'énergie électronique du TDMAE [tetrakis(diméthylamino)éthylene]
Last Update: 3 February 2014