Electric field effect in the growth of carbon nanotubes

Abstract

The growth of carbon nanotubes (CNTs) under a controlled electric field in a chemical vapor deposition system is investigated. We evaluate the influence of this external field on the morphological and structural characteristics of CNTs. Scanning electron microscopy results display a large presence of carbonaceous material in the positive plate, which appear to be a consequence of the attraction of electric forces over the electronically unbalanced cracked carbon molecules in the heating zone. We also observe a growth behavior for CNTs, in which catalyst particles are localized either at the bottom or the upper part of the nanotube, depending on the intensity and direction of the electric field. A Raman analysis from all obtained carbon materials shows the presence of two peaks, corresponding to the D * 1340 cm -1 and G * 1590 cm -1 bands attributed to multiwall CNTs. The average diameter of the CNTs is in the range between 90 and 40 nm. These results provide experimental evidence for the dependence of the catalyst and subtract interaction on the growing mechanism, in which weak chemical or electronic interactions could stimulate a top-growing as the strongest base-growing process.

Observation of Charge Generation and Transfer during CVD Growth of Carbon Nanotubes

“…It is worth noting that the effect of external electric fields on the growth of CNTs has been already discussed in previous literature. Most of the work focused on the electric-field-directed effect for growing CNTs by using DC or AC electric field. − The reason for the CNTs’ orientation was interpreted as the extra charge from the electrodes or the high polarizability of CNTs. However, the charge generation phenomenon during the growth of CNTs has not been noticed. − Just before submitting this paper, we found Smovzh and colleagues’ paper.…”