Fabrication and field emission property studies of multiwall carbon nanotubes

Well-aligned and randomly grown multiwall nanotubes (MWNTs) fabricated by the radio-field-induced self-bias hot-filament chemical vapour deposition method demonstrate that the growth mechanisms are either 'tip growth' or 'base growth' depending on the size of the catalyst metal particles involved. The carbon nanotubes (CNTs) can also be successfully grown on iron-like bulk alloys when preceded by hydrogen plasma etching. The high yield of CNT fabricated on oxidized metal alloys is attributed to the high active surface area that ensues from etching. The change in field emission currents of MWNTs with temperature is not sensitive but is detectable within the range 300-20 K. This is interpreted to be due to the high aspect ratio of CNTs.