The Energetics of Charge Transfer Processes

As already mentioned in the previous section, any electron transfer across the semiconductor-liquid interface occurs via the energy bands. There may also be 

A variation of the concentration of one of the redox species leads to a change of the redox potential and of the Fermi energy fpredox given by the Nernst equa- 

As already mentioned in the previous section, any electron transfer across the semiconductor-liquid interface occurs via the energy bands. There may also be an electron transfer via surface states at the interface the electrons or holes, however, must finally be transported via one of the energy bands. This is possible by capturing an electron from the conduction band or a hole from the valence band in the surface states. In the present section the basic rules for the charge transfer will be given, in particular, physical factors which determine whether an electron transfer occurs via the conduction or the valence band, will be derived. For illustration, the Gerischer model will be used here because it best shows the energetic conditions. 

According to measurements of the space charge capacity dependent on the electrode potential (Mott-Schottky measurements, see Section 5.3), any variation of the electrode potential leads usually only to a corresponding change of the potential, 

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