Emission characteristics of niobium nitride field emitters

Field emission cathodes have been examined to be applied to electron beam systems such as electron microscopes and electron beam exposure systems. The most important factors for such cathodes are brightness and stability. Field emission cathodes are very bright, but the electron emission fluctuates greatly. Materials for the field emission cathode should be examined systematically with a view towards stable emission. Nitride needles of transition metals of Nb are obtained by heating elemental metal needles in an ammonia gas atmosphere. The NbN needle gave the most stable field emission current among the niobium nitrides examined here.