A comparative study of electron injection into ZnO, CdS and CdSe single crystal anodes

Abstract

AbstractThe anodic behaviour in darkness of the n‐type semiconductors ZnO, CdS and CdSe in contact with solutions of indifferent electrolyte and of one‐equivalent reducing agents was studied by capacity and current measurements. The same group of strong reducing agents appeared to be able to inject electrons into the conduction band of the three electrodes investigated. Making use of the capacity results and of literature data on redox potentials, an energy diagram was constructed in order to compare the position of the band edges of the semiconductors with that of the redox levels in the electrolyte. A relationship was found between the relative energetic height of these levels and the injection behaviour. The results indicate that the filled energy levels in the redox electrolyte are spread over a rather wide energy range.