Liquid carbon, carbon-glass beads, and the crystallization of carbon nanotubes.
The formation of carbon nanotubes in a pure carbon arc in a helium atmosphere is found to involve liquid carbon. Electron microscopy shows a viscous liquid-like amorphous carbon layer covering the surfaces of nanotube-containing millimeter-sized columnar structures from which the cathode deposit is composed. Regularly spaced, submicrometer-sized spherical beads of amorphous carbon are often found on the nanotubes at the surfaces of these columns. Apparently, at the anode, liquid-carbon drops form, which acquire a carbon-glass surface due to rapid evaporative cooling. Nanotubes crystallize inside the supercooled, glass-coated liquid-carbon drops. The carbon-glass layer ultimately coats and beads on the nanotubes near the surface.
de Heer
Walt A
WA
School of Physics, Georgia Institute of Technology, Atlanta, GA 30332, USA. walt.deheer@physics.gatech.edu
Poncharal
Philippe
P
Berger
Claire
C
Gezo
Joseph
J
Song
Zhimin
Z
Bettini
Jefferson
J
Ugarte
Daniel
D