The influence of dielectric properties on the emission of a metal-dielectric-metal system: Traps, discussion of the transfer ratio

Abstract

Under the assumption that the Fowler-Nordheim equation holds for the leakage current the influence of traps on the emission current from the sandwich cathodes is investigated. A simple model, describing the capture of electrons at the localized states in the forbidden band of the dielectric, their liberation by a thermal emission or by a field, the transmission of these electrons through the top metal electrode and the transfer into vacuum, has been proposed for this purpose. The expression obtained for the transfer ratio α is then discussed and compared with the other expressions derived in a preceding paper for ideal dielectrics, for dielectrics containing an elastic scattering mechanism and for electron-optical phonon interactions. It is shown that at the same intensity of various scattering processes the traps reduce the emission current to the highest degree.