Pulsed Microplasma Using Carbon Nanotubes for Cathode

Abstract

Using carbon nanotubes (CNTs) or a flat Pt film for the cathode, microplasma was produced in a scanning electron microscope (SEM) chamber containing Ar gas at nearly atmospheric pressure, with gap lengths from 10 to 800 µm. Field electron emission measurements were carried out in the SEM chamber, and gas discharges were conducted at the same configuration in a gas cell installed in the SEM chamber. The ignition voltages using the CNT cathode were much lower than those using the flat Pt cathode under the same conditions, because of the field electron emission. The ignition of gas discharge using the CNT cathode was reproducible every time, because of the ensured supply of primary electrons. It was suggested that the pulse discharge using the CNT cathode was a convolution of the discrete electron avalanche originating from the field emission.