Fabrication of large current density carbon nanotube based field emitters

A synthesis of carbon nanotubes(CNT) for field emission was grown speedly and vertically by microwave plasma chemical vapor deposition with a multi-layered stack as the catalyst lay. The SEM and TEM analysis results of the CNT samples showed that as-grown CNT were typical multi-layered ones with few defects, aligned and straight, and uniform in diameter and length. The growth rate of CNT was more than 5 μm/min. The field emission results showed that the as-grown CNT emission array presented excellent and stable field emission with current density more than 6 A/cm2. The work function of the as-grown CNT was 4.59 eV measured by UPS and the corresponding field factor was about 1 400.