The Anodic Decomposition Mechanism of n ‐ GaP Electrodes: A Hole Injection Study

Abstract

A new and simple method is presented for studying the mechanism of anodic decomposition of n-type III-V electrodes. The method can be applied when decomposition, resulting from the hole injection, gives rise to surface intermediates, capable of thermally injecting electrons into the conduction band. As an example, the n-GaP/Ce/sup 4+/ system was studied. Reduction of CE/sup 4+/ proceeds by injection of holes which cause anodic dissolution. The rate of thermal excitation during anodic dissolution, measured via the limiting anodic current, was studied as a function of the rate of hole injection and of temperature. The results were quantitatively interpreted on the basis of a decomposition model including hole steps, chemical reaction with water and one thermal excitation step. The energy of the surface states from which electrons are excited into the conduction band was determined.