Optically generated space charge layer in insulators: Electrolyte electroreflectance at the BiI3/electrolyte interface

Abstract

AbstractElectrolyte electroreflectance (EER) is a powerful technique for studying important properties of the semiconductor/electrolyte interface such as the flatband potential and the density and distribution of surface states. EER is, however, usually restricted to semiconductors and metals, the required electrical field strength being present in the space charge and Helmholtz layer, respectively. We report now about EER measurements on high resistivity BiI3 electrodes where the space charge — and therefore the resulting electrical field — is generated optically, i.e. by background irradiation. At the same time, the latter leads to a huge enhancement of the photoresponse.