On the nature of the inhibition of electron transfer at illuminated p-type semi¬con¬ductor electrodes

A rather strong inhibition of the cathodic photocurrent is reported for various p—type semiconductor electrodes which would lead to a severe loss of energy when such electrodes are applied in solar energy conversion systems. In this paper results are presented for var ious redox systems at GaAs and InP which exhibit quite different beha vior with respect to the inhibition of the cathodic photocurrents. The nature of the inhibition is discussed in terms of two different models, in one case an efficient back reaction via the valence band (recombina— tion shunt in the electrolyte), in the other strong recombination via surface states is assumed.