Activation of fullerene coatings on field emitters by potassium atom and ion fluxes

Use of ion processing to improve the quality of fullerene-coated field emitters

“…AND EQUIPMENT Experiments were carried out with a multifunc tional vacuum setup (for details, see [5,6]) equipped with a field microscope-projector, which allows online high resolution (1.5-2.0 nm) monitoring of the surface relief of tip cathodes and spatial distribu tion of electrons emitted from such cathodes. The setup was also provided with a system of fullerene coating deposition on the tip cathode surface and also with a source of potassium ions used for processing.…”

“…It has been demonstrated [5,6] that fullerene coated tip emitters can be activated by a potassium ion flux. Specifically, it has been found that exposure of a fullerene coating to a flux of slow potassium ions (with an energy of 40-100 eV) lowers the work function owing to the formation of metallofullerenes such as endohedrals C 60 @K or exohedrals K@C 60 .…”

“…Ion activation makes it possible to considerably (almost twofold) reduce the operating voltage necessary for extracting the field emission current from a tip cathode. In essence, the authors of [5,6] have demonstrated for the first time the feasibility of improving the quality of fullerene coated emitters by ion beam processing. Studies on the influence of ion bombardment on the performance of such emitters have continued.…”

“…Specifically, it has been found that exposure of a fullerene coating to a flux of slow potassium ions (with an energy of 40-100 eV) lowers the work function owing to the formation of metallofullerenes such as endohedrals C 60 @K or exohedrals K@C 60 . Rapid one stage and longer term three stage techniques of ion activation have been developed [5,6]. Ion activation makes it possible to considerably (almost twofold) reduce the operating voltage necessary for extracting the field emission current from a tip cathode.…”

“…It is believed that specially coated carbon and carboniferous emitters are highly stable against gaseous media and ion bombardment in high voltage devices operating in technical vacuum (see, e.g., [1,2]). Fullerene coatings suitable for field emitter protection have been developed and studied in [3][4][5][6][7].…”