Electron field emission from carbon nanotubes in atmospheric pressure Ar gas

Electron field emission (FE) from carbon nanotubes (CNTs) in atmospheric pressure Ar gas was measured. The FE measurements were carried out using a needle for anode and a CNT specimen for cathode. The FE current usually appeared at several hundred volts at applied voltage to the anode at the gap length from 15 to 100 μm. When the applied voltage was lower than a conventional gas breakdown voltage around 300 V, the FE in Ar gas was stable and reproducible even at atmospheric pressure. There was no damage on the surface of CNT cathode in SEM observation after the FE operation in Ar gas. When the applied voltage was increased to more than the gas breakdown voltage, a conventional gas discharge took place resulting in destroying the CNT cathode surface.