Cold-emission film-type cathode and method for producing the same

The present invention may be used in the production of highly efficient films for electron field emitters. The cold-emission cathode of the present invention comprises a substrate having a carbon film with an irregular structure applied thereon. This structure comprises carbon micro- and nano-ridges and/or micro- and nano-threads which are perpendicular to the surface of the substrate, which have a typical size of between 0.005 and 1 micron as well as a distribution density of between 0.1 and 100 mum-2, and which are coated with a diamond nano-film whose thickness represents a fraction of a micron. The method for producing the cathode involves sequentially depositing two carbon films. A carbon film with nano-barbs is first deposited on a substrate arranged on an anode by igniting a direct-current discharge at a density of between 0.15 and 0.5 A. This deposition is carried out in a mixture containing hydrogen and a carbon-containing additive, under a global pressure of between 50 and 300 torrs, using vapors of ethylic alcohol at a 5 to 15% concentration or vapors of methane at a 6 to 30% concentration, and at a temperature on the substrate of between 600 and 1100° C. A diamond nano-film is then deposited on the graphite film thus grown.