Electrical characteristics of microplasma devices with carbon nanotubes (CNTs) as the cathode

The experimental results of glow discharge in microplasma devices are presented. Different constructions of the cathode are investigated. Breakdown voltage as a function of pressure of each cathode structure is recorded and the comparison to Paschen´s curve is made. The voltage-current characteristics of each cathode construction are studied with two different background gases and fixed pressures. One microplasma device uses CNTs as the cathode. The hollow structure is achieved by placing a dielectric layer with a center hole over the planar CNTs fabricated on a silicon wafer by the chemical vapor deposition (CVD). The anode is a metal attached to the surface of the dielectric. It is shown that the cathode with CNTs has a lower ignition voltage at the initial stage of breakdown, due to the enhanced field emission characteristics of CNTs. The device is operated in the pressure range of 50 to 750 Torr with DC applied voltage and the results are compared with and without CNT in the hollow cathode structure.