Theory of Capacitance‐Voltage Characteristics of Semiconductor Electrodes with Interface States

Theory of characterization method for semiconductor electrodes with interface states has been developed under the assumption that the interface states are in quasi‐equilibrium with the electrolyte. Model calculation based on this theory has well reproduced the observed C‐V characteristics in electrodes. It is pointed out that dispersive Mott‐Schottky plots give a variety of information about energetics of a semiconductor‐electrolyte contact. The surface structure of the electrode has been clarified in some detail. Some electrodes may have two types of interface states. The distribution of the shallower one can be expressed by a gaussian with a standard deviation of ∼800Å, and the deeper one by an exponential function with deep penetrating length. The interface state seems to be the reason why electrodes have a large quantum efficiency.