STUDY OF REACTION COUPLING AND INTERFACIAL KINETICS AT SEMICONDUCTOR ELECTRODES BY BAND EDGE SHIFT MEASUREMENTS

Through band edge shift (BES) measurements the paper puts forward new aspects concerning the study of reactions that take place at the semiconductor/electrolyte interface. In particular it focuses on the problem raised by reaction coupling, that is the interdependence between the redox and the photocorrosion reactions at photoanodes for instance. BES determination coupled with stabilization characterization was performed with n-GaAs photoanodes in contact with various redox solutions. With respect to surface charging, it is shown that reactions do not always act in parallel; surface effects (adsorption of redox species for example) may strongly affect the reaction scheme. For the simplest case (reaction in parallel) we propose a way of determining the electrode stability from BES measurements.