Growth and field emission of multi-walled carbon nanotubes

Vertically-oriented multi-walled carbon nanotubes (MWCNT) were grown via thermal chemical vapor deposition (TCVD) technique under different conditions by using a hydrocarbon gas (ethylene) and a reactive gas (hydrogen). In addition, a Plasma-Enhanced CVD station has been assembled by our group in order to grow vertically-aligned MWCNTs using another hydrocarbon gas (acetylene) and reactive gas (ammonia). These MWCNT will be studied for application to high-power microwave (HPM) amplification and field emission displays. A pulsed diagnostic circuit was designed to minimize the effect of stray capacitive current and was used during the field emission measurement to maximize the emission current while avoiding arcing. Results revealed an emission current of up to 0.8 A/cm2 from the MWCNTs at an applied anode voltage of 6kV. Collected field emission current data was analyzed by using Fowler-Nordheim equation. Careful analysis of such results demonstrated potential for the MWCNTs to be developed into high current-emitting cathodes.