G. Nogami et S. Ohkubo, CURRENT RESPONSES TO AN IMPULSE LASER-LIGHT ILLUMINATION IN SEMICONDUCTOR ELECTRODES, Journal of the Electrochemical Society, 143(7), 1996, pp. 2220-2225
An impulse current response to a short laser pulse was measured using
a current-voltage converter with a zero input resistance, which enable
d us to provide any band bending of a semiconductor electrode under a
potentiostatic condition. The current transient can monitor a net char
ge-transfer process across a semiconductor-electrolyte interface becau
se the external resistance is almost zero. The current transient was f
ound to be characterized by a relaxation time tau = (R(dl) + R(soi))C-
sc where R(dl), R(sol), and C-sc are the diffuse double-layer resistan
ce, the solution resistance, and the depletion layer capacitance of th
e semiconductor. C-sc obtained from the analysis of the current transi
ent gave an ideal Mott-Schottky plot. By intentionally increasing the
diffuse layer thickness with which R(dl) and then tau increase, the dy
namics of protons generated as an oxidation product of water was confi
rmed to be monitored from the current transient.