Emission properties of carbon nanotubes and cathodes on their basis

Abstract

This paper reviews the main physical problems and the most important results related to the emission properties of carbon nanotubes (CNT) and cathodes on their basis. The phenomenon of electrical field amplification in the vicinity of a nanotube tip of various structures is studied quantitatively. The physical mechanisms responsible for deviation of the current–voltage characteristics of a nanotube's array from those for an individual CNT described by the classic Fowler–Nordheim relation have been considered. The types of arrangement of CNTs over the cathode surface are compared and analyzed in terms of the screening effect. The thermal effects limiting the emission current of a CNT-based cathode have been treated. The angular divergence of an electron beam emitted by a CNT caused by electron Coulomb repulsion has been evaluated.