Surface Barrier Analysis for Metals by Means of Schottky Deviations

Abstract

The transmission coefficient for the mirror-image barrier at a metal surface is applied to the case of photoelectric emission. The distribution over which the coefficient is averaged is that given by Fowler for energies normal to the emitter surface, and is altered by the Schottky barrier lowering. The average differs from unity by an amount the major part of which is a periodic function of the accelerating field, giving a periodic deviation from the photoelectric Schottky effect which differs from the thermionic deviation only in amplitude. A refinement in the computation of the unaveraged periodic transmission coefficient brings the theory for thermionic deviations into agreement with that of Miller and Good. The improved form of the thermionic deviation is applied to experimental data to evaluate the complex reflection coefficient $\mu$ characterizing the potential form in the immediate vicinity of the surface. The values of $\left|\mu \right|$ so obtained for the highly refractory metals are of the order of 0.4, as compared with 0.2 predicted on the basis of the box model.