Thermal Conditions Favoring Buckytube Growth on the Anode

Abstract

ABSTRACTThe most widespread methoid for buckytube synthesis is by arc discharge in an inert gas ambient. At arc discharge the major kind of charge carriers are the electrons generated from the cathode by thermal emission. For this reason up until now the deposit was always obtained on the cathode. By supplementary electrode heating and cooling we studied the effects of the anode-cathode temperature difference and found that it plays a major role in defining the quality and quantity of the deposit obtained. Given appropriate heat-up or cool-down of the electrodes, a state can be reached such that the temperature at the cathode is higher than the temperature at the anode. A deposit was obtained on the anode, observed by a TEM. In our view employing this method yields the most favorable conditions for buckytube growth. Our results show that except buckytubes with a high ratio of their length with respect to their width, a multitude of small size polyhedral carbon systems closed in by spatial carbon nets and thin flat interfering carbon plates were also obtained. When using electrodes of different cross-section, with the deposition of an ever thicker deposit on the anode, its temperature regime changes. The lower initial temperature at the anode begins to grow steadily with time tending towards the temperature at the cathode. Thus, buckytube growth proceeds at the lowest possible rate, at a small temperature difference between the vapor source and growing structure. In our view employing this method yields the most favorable conditions for buckytube growth.