Process and characteristics of the large area well-aligned CNTs with open ends by electron cyclotron resonance chemical vapor deposition

This work presents a simple and highly reproducible method for fabricating well-aligned carbon nanotubes (CNTs) with open ends and large areas. The process involves the following steps. Co-assisted well-aligned CNTs were firstly synthesized by electron cyclotron resonance chemical vapor deposition (ECR-CVD) using H-2 and CH4 as source gases. Then, the as-grown CNTs were post-treated in an atmosphere of H-plasma to remove the carbon layers that covered the surface of the catalyst. They were then immersed in 0.25 M HNO3 solution to remove the catalysts from the tips. Their structures and characteristics in each processing step were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and field emission (FE) J-E measurements. The results indicate that the open-ended CNTs may behave better properties than the as-grown tubular CNTs because they have a higher local aspect ratio around the open-ended tips, if their structural integrity is maintained after post-treatment. (c) 2005 Elsevier B.V. All rights reserved.