DC plasma enhanced growth of oriented carbon nanowall films by HFCVD

Two dimensional graphitic carbon structures, commonly referred to as carbon nanowalls (CNW), are raising increasing interest in the scientific community. Their surface area is theoretically twice that of the closed boundary structures, such as carbon nanotubes, making them extremely attractive for chemical and biosensor applications. In this work CNW, with maximum longitudinal dimension ranging from 10 to 200 nm and wall thickness lower than 5 nm, have been grown in a HFCVD reactor on Si substrates. The growth precursors consisted of methane diluted into He noble gas. The effect of a DC plasma on the growth rate and film morphology was explored. The experimental setup consisted of a two grid system which allowed to vary independently the plasma voltage and current density on the substrate surface. An increase of growth rate was observed as the film thickness increased from a few nanometers to about 200 nm when the substrate current density was increased from 0 to 3.5 mA/cm(2) for 30 min. (c) 2006 Elsevier B.V. All rights reserved.