The influence of adsorbed ions on charge-carrier recombination at the n-GaAs photo-anode surface

Photocurrent-voltage and capacitance-voltage measurements were performed at the n-GaAs/aqueous electrolyte interface before and after the pre-treatment of the surface in solutions containing Pb2+ or Ru3+. The results confirm the model, proposed before, in which two types of surface states were assumed to participate in electron-hole recombination, i.e. non-photo-induced states as well as states associated with photodecomposition intermediates, and demonstrate that, whereas the pre-treatment enhances the rate of recombination in the former type of states, it does not significantly affect the rate of recombination in the latter, nor that of interfacial charge transfer.