Surface Charging Effects during Photoanodic Dissolution of n ‐ GaAs Electrodes

Abstract

The photoanodic dissolution of n-GaAs was investigated in an electrolyte, 0.1M EDTA solution at pH 5, in which oxide formation can occur at higher light intensity. The effect of illumination and film formation on the charge and potential distribution of the electrode was studied by means of impedance measurements. A model involving positively charged states at the semiconductor/oxide interface is developed to account for the buildup of a high surface charge density during illumination. The importance of surface oxide and interface charge for photoanodic reactions is considered in terms of this model. © 1983, The Electrochemical Society, Inc. All rights reserved.