Field emission spectroscopy from (111) flat and stepped planes of iridium

Abstract

Total energy distribution measurements of electrons field‐emitted from clean iridium (111) plane, prepared by low temperature field evaporation, reveal two types of spectra which differ essentially by a structure at 0.45 eV below the emitter Fermi level. Work function results for clean and hydrogen covered surfaces are presented and used in order to determine whether the probed region of the surface is flat or stepped. It is shown that the spectra exhibit a free electron behaviour without any structure when the surface is flat, while current contribution from edge atoms on the stepped surface gives rise to a structure at 0.45 eV.