Effective parameters on diameter of carbon nanotubes by plasma enhanced chemical vapor deposition

The effective parameters on the diameter of carbon nanotubes (CNTs) by plasma enhanced chemical vapor deposition (PECVD) were presented. Among lots of influential parameters, the effects of the catalytic film thickness and the pretreatment plasma power on the growth of CNTs were investigated. The results show that the size of catalytic islands increases by increasing the thickness of catalytic layer, but the density of CNTs decreases. The pretreatment duration time of 30 s is the optimal condition for growing CNTs with about 50 nm in diameter. By increasing the pretreatment plasma power, the diameter of CNTs decreases gradually. However, the diameter of CNTs does not change drastically from 80 to 120 W. The uniformly grown CNTs with the diameter of 50 nm are obtained at the pretreatment plasma power of 100 W.