Electron Emission Devices Using Carbon Nanocoils

Abstract

We have found out that carbon nanocoils have a highly potential ability for an electron emission device. Carbon nanocoils were prepared in high yield by catalytic thermal chemical vapor deposition. The source gas and catalyst are acetylene and iron-coated indium tin oxide, respectively. The measurement of the field emission current from the nanocoils at a pressure of 1 × 10−6 Torr shows the turn-on voltage as low as 180 V at the electrode gap of 130 μm and the saturation current density more than 10 mA/cm2, which is similar to or smaller than those of most carbon nanotube emitters. The fluorescence is more uniform compared with that of the nanotube emitters. The fluorescence experiment also indicates that the body as well as the tip of a coil work as an effective emission site. A lifetime test for 100 hours under the current density of 1 mA/cm2 shows no large fluctuation. These results indicate that the nanocoils have a spatially uniform emission of electrons and a long stability.