Field Emission Enhancement of Carbon Nanotubes by Surface Modification

By employing a multi-walled carbon nanotube (MWCNT) film as the substrate, we obtain Fe tipped carbon nanorods or carbon nanoparticles grown on the outer walls of MWCNTs by combining sputtering deposition of Fe films and rf plasma enhanced chemical vapour deposition at high temperature. Scanning electron microscopy and high-resolution transmission electron microscopy are used to examine the structure of carbon nanorods and carbon nanoparticles. In addition, the formation mechanism is discussed briefly. The electron field emission tests indicate that the turn-on field (at 10μA/cm²) of the treated MWCNT films decreases from 2.4V/μm to 0.79V/μm and the field emission current is relatively stable. The enhanced field enhancement factor, increasing emission densities coming from the grown nanorods and nanoparticles, and H terminated by H plasma all are responsible for the enhancement of the field enhancement factor.