Field emission properties of carbon nanotubes and its application to flat panel display

We have investigated field emission properties from an individual carbon nanotube protruded ∼ 45μm from a tungsten needle tip. The I-V characteristics of the field emitter show no emitter-collector gap dependence at a gap less than 310μm. This experimental result is explained by an analysis under a consideration of the nonuniform electric field near the tip of the nanotube. The tip radius of 2.7nm, which is obtained from the analysis, is consistent with the average tip radius of nanotubes. The field emission device for a flat panel display consisting of the well perpendicularly aligned carbon nanotube array is fabricated by the catalytic chemical vapor deposition using C2H2 as source gas. Patterned emission device is easily obtained by patterning the catalyst. The threshold voltage for the field emission decreases from 400V to 150V by the thermal treatment in air at 700°C for 8min. We also demonstrate that the diode type display consisting of a phosphor coated electrode and the nanotube device emits strong and uniform luminescence.