Field emission of carbon nanotubes grown on carbon cloth

Field emission from carbon nanotubes grown on carbon cloth has been studied. An extremely low electric field of less than 0.4 V/mum is required to reach an emission current density of 1 mA/cm(2). This ultralow operating electric field of carbon nanotubes grown on carbon cloth is mainly due to a very high field enhancement factor of 1.882x10(4), which is the result of geometrical configuration of the carbon nanotubes and the substrate. In addition to the field enhancement, the highly disordered microstructure of carbon nanotubes grown on carbon cloth plays an important role to field emission. This unexpected result indicates that the roughness of the substrates on which carbon nanotubes grow is very important. This result also brings us significantly closer to practical applications such as highly efficient lamps, field emission displays, micro vacuum electron sources, etc. (C) 2004 American Institute of Physics.