Robust and regenerable integrally gated carbon nanotube field emitter arrays

We have grown multiwalled carbon nanotubes by chemical-vapor deposition on two types of gated structures, one containing a silicon post, and another having an open aperture. A gate current to anode-current ratio of 2.5%, the lowest of any nanotube field emitter arrays was measured for the open aperture configuration. The silicon post structures produced 1-nA emission current at gate voltages below 20V and up to 1mA at 40V (from 0.5-mm2 area). The emission was relatively stable compared to other field emitter arrays and destructive arcing was not observed. The gate voltage needed to produce a given emission current was reduced by adsorbed water vapor and was unaffected by xenon. Emission in hydrogen at pressures near 10−4Torr also increased the emission current, and restored a large fraction of the original emission current to arrays degraded by operation in oxygen. Electron energy distributions broaden and shift to lower energies at higher emission current. The broadening can be explained by the potentials developed at the silicon-nanotube contacts, and at the nanotube-vacuum interface.