The optimization of carbon nanotube growth parameters for photonics

Abstract

Suspended carbon nanotubes are of particular interest for optical and optoelectronic applications because of their superior optical properties. The purpose of this work is to explore sample preparation and chemical vapour deposition (CVD) process parameters to develop methods of fabricating large quantities of freely suspended single walled carbon nanotubes (SWNTs). Parameters including CVD hydrogen soak temperature, growth temperature, choice of catalyst, gas flow rate, and gas composition were examined. Various techniques were tested for their practical capability to suspend SWNTs. A simple procedure was used to suspend SWNTs over networks of randomly organized thick MWNTs on unpatterned substrates. In a more versatile procedure SWNTs were suspended between adjacent pillars of vertically aligned MWNT forests on patterned substrates. Large quantities of SWNTs were also suspended over pre-fabricated trenches in the substrate. All of these laterally suspended SWNT were found to be useful for optical studies.