Some aspects of the use of carbon materials in field electron emission cathodes

A detailed analysis has been carried out of the advantages and disadvantage s of using carbon fibers and flat graphite structures with activated surfac es as materials for field electron emission cathodes. In this article we pr esent the results of original experimental studies on the elementary compos ition of carbon materials and on the effect of thermal annealing on their s tructure and emission properties and on the reduction of the work function when cesium is implanted into these materials. We also assess the potential of irradiation techniques for producing flat field emission cathodes with activated surfaces, and discuss a method for predicting how the shape of th e emitting surface changes as a result of bombardment by low-energy residua l-gas ions. Suggestions are made about the best design of field electron em ission cathodes for various practical purposes. (C) 2001 American Vaccuum S ociety.