Analysis of Trapping and Recombination Effects in Photoelectrochemical Processes at Semiconductor Electrodes: Investigations at n‐GaAs

Fast impedance measurements have shown that reliable flatband potentials of GaAs can only be obtained using high scan rates. Illumination leads to a shift of energy bands at the interface which is interpreted by hole trapping in surface states. A recombination conductance determined by impedance measurements is used to characterize the recombination of minority carriers injected by light or a redox system. A semiquantitative model is discussed according to which the recombination occurs mainly in the space charge region of the semiconductor.