Field emission characteristics of carbon nanotubes fabricated by microwave plasma enhanced chemical vapor deposition

摘要

We have developed a process to fabricate sharpended top and open-edged carbon nanotubes (CNTs). The process consists of oxygen plasma ashing and magnetic field gradient treatment. By the oxygen plasma ashing treatment, the diameter of CNTs was sharpened from 100 nm to 50 nm. The turn-on field votage, for an emission current density of 1 nA/cm~2, was 0.8 V/ mu m. At current density of 1 mA/cm~2, the field voltage achieved was 2.0 V/ mu m in the case of CNTs fabricated by oxygen plasma ashing treatment. Catalyst metal particles on top of the CNTs were successfully removed by magnetic field gradient treatment. The emission current density and turn-on voltage of the CNTs after magnetic field gradient treatment was improved, being better than that of as-grown CNTs.