Bias effect on the growth of carbon nanotips using microwave plasma chemical vapor deposition

Carbon nanotips with a high-aspect ratio were directly grown on Pt films. Carbon nanotips grew up to 5.4 μm length and 64 nm diameter under a −120 V bias. Compared to the hollow structure of carbon nanotubes, transmission electron microscopy images indicate its solid body, which is made of graphite. Carbon nanotips possess good field emission characteristics, that is, a turn-on field of 1.5 V/μm and 761 μA/cm2 under 2.2 V/μm. The Pt films provide a good conduction path for electron transport from the cathode to the emission site and do not act as catalysts.