Cn. Kenyon et al., ANALYSIS OF TIME-RESOLVED PHOTOCURRENT TRANSIENTS AT SEMICONDUCTOR LIQUID INTERFACES, Journal of physical chemistry, 97(49), 1993, pp. 12928-12936
Small signal photocurrent transients have been measured for n-Si/CH3OH
-Me2Fc+/0/Pt, n-Si/Au/CH3OH-Me2Fc+/0/Pt, n-Si/Pt/NaOH(aq)/Ni(OH)2/Ni,
n-TiO2/NaOH(aq)/Ni(OH)2/Ni, and n-TiO2/NaOH(aq)-Fe(CN)63-/4-/Pt cells.
Even though the radio-frequency and microwave conductivity signals fo
r photoexcited n-Si/CH3OH-Me2Fc+/0 contacts persist for > 100 mus, the
photocurrent transients for these interfaces decayed in <10 mus and w
ere limited by the series resistance of the cell in combination with t
he space-charge capacitance of the semiconductor. An equivalent circui
t model is presented and physically justified in order to explain this
behavior. The model is also used to elucidate the conditions under wh
ich photocurrent transients at semiconductor electrodes can be expecte
d to yield information regarding the faradaic charge-transfer rate acr
oss the semiconductor/liquid interface.