Influence of the Plasma Condition on the Morphology of Vertically Aligned Carbon Nanotube Films Grown by RF Plasma Chemical Vapor Deposition

Abstract

Vertically aligned carbon nanotube (VACNT) films have been grown by RF plasma chemical vapor deposition (RF-PECVD) with a controlling plasma condition. From the in situ optical emission spectroscopy (OES) and self-bias measurements, we have investigated the relationship between the morphology of VACNTs and the plasma condition in PECVD. CH radical and atomic hydrogen peaks were prominent in the OES spectra of CH 4 plasma. The plasma condition was changed by varying the interelectrode distance in PECVD. With increasing interelectrode distance, the diameter and density of VACNTs increased as a result of the increase in plasma density, the fraction of CH radicals, and self-bias. It is likely that the fraction of CH radicals in plasma influences promotion of the growth of CNTs, while the self-bias induces their vertical alignment.