Abstract
Three separated growth sequences of vertically-aligned carbon nanotubes (CNTs) were successfully synthesized for the first time on porous silicon (PSi) by modifying the catalyst-nanotemplate interaction in a two-stage hot filament assisted chemical vapor deposition. The morphological differences between the aligned CNTs grown by various flow rates were investigated by means of FESEM images. The presence of single-wall CNTs (SWCNTs) was confirmed by Raman radial breathing mode peak between 100 and 400 cm-1. The low operating electrical field of the multilayer VACNTs grown on PSi is attributable to a relatively high field enhancement factor, which is the result of the geometrical configuration of the CNTs and the substrate. The findings demonstrate that multilayer CNTs have been identified as promising candidates for field emitters in numerous applications such as electron microscopy, flat panel display, as well as other advanced technologies.