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Lecture J.P. Colomer


23 februari 2006 FWN-Building 5116.0116, Nijenborgh 4, 9747 AG, Groningen
Speaker:Dr. J.P. Colomer
Affiliation:Facultes Universitaires Notre-Dame de la Paix
Title:Electron microscopy and diffraction study of carbon nanotubes
Date:Thu Feb 23, 2006
Location:FWN-Building 5116.0116
Host:P. Rudolf
Telephone:+31 50 363 4736


The structure of bundles of double-walled carbon nanotubes, synthesized by catalytic chemical vapor deposition (CCVD), has been analysed using transmission electron microscopy (TEM) and electron diffraction (ED). First, small and straight bundles have been characterized. The unambiguous presence of double-walled carbon nanotubes is revealed both by direct images and electron diffraction. TEM observations of a bundle of double-walled nanotubes are possible with the electron beam perpendicular or parallel to the bundle axis. In both cases, we have direct evidence of the packing of double-walled nanotubes in a hexagonal arrangement inside the bundles. By ED we found that, in a sample produced by CCVD, most of the smaller bundles are constituted of identical double-walled nanotubes. This finding gives a strong indication on the mechanism for the growth of these bundles. Their growth most likely results from a collective growth mechanism of the nanotubes composing each individual bundle and taking place on a single metal catalyst particle. Bundles of double-walled carbon nanotubes forming rings have also been observed. The analysis of the real-space images shows that the rings are constituted of coiled bundles of double-walled nanotubes. The ED pattern realized on one of these rings can be completely explained with the help of simulations based on the kinematical theory. To conclude, the last development in the study of the structure of individual carbon nanotubes by electron diffraction will be shown.
Laatst gewijzigd:22 oktober 2012 14:30