Pm. Ajayan et al., GROWTH MORPHOLOGIES DURING COBALT-CATALYZED SINGLE-SHELL CARBON NANOTUBE SYNTHESIS, Chemical physics letters, 215(5), 1993, pp. 509-517
We report interesting growth morphologies produced during the electric
arc-discharge between a graphite cathode and a composite cobalt-graph
ite anode, which includes the abundant formation of single-shell carbo
n nanotubes of 1-2 nm diameter. As the pressure inside the chamber and
the cobalt content of the electrode are varied these ''carbon monotub
es'' are formed in bundles and in high density under certain condition
s in the soot, webs and string-like structures that decorate the chamb
er and also on a collaret that forms around the conventional deposit c
ontaining multi-shell nanotubes. We present high-resolution transmissi
on electron microscopy images of these structures and propose conditio
ns that promote single-tube growth. We also notice, in some cases, nov
el formation of regularly spaced cobalt particles enclosed in graphiti
c capsules and surrounded by sheaths of soot.