Tunnelling through thin adsorbed films in ion discharge at limiting current—I. Potential barriers and analytic equations

Abstract

The shape of potential barriers and the basic equations of the tunnelling limiting current are established for the following interfaces: metal/electrolyte, metal/thin-dielectric-film/electrolyte and metal/thin-semiconductor-film/electrolyte. The occurrence of the thin adsorbed films explains well the formation and the isolation of the metal dendrites at the dme. Owing to the very large number of electrons striking the inner metal surface, the tunnelling thickness in solution seems to be greater than 10 Å, while the tunnelling thickness in solid films are generally considered to be of the order of 10–100 Å. A general mechanism for electrolytic metal powder formation is proposed, taking into account electron tunnelling through thin solid films and at the metal/electrolyte interface. An important role is attributed to the formation of metal spikes.