PHOTOCURRENT MULTIPLICATION AT P-TYPE SEMICONDUCTOR ELECTRODES

A review is presented of photoelectrochemical systems which at p-type semiconductor electrodes give a quantum efficiency greater than one. T he use of intensity modulated photocurrent spectroscopy (IMPS) for stu dying such systems is considered. Special attention is devoted to the mechanism of current-doubling at p-GaAs caused by oxidizing agents whi ch also etch the semiconductor chemically. New data are presented for the photocathodic reduction of iodate in alkaline solution at p-GaAs. At low light intensity this system gives a quantum efficiency (Q) clos e to 6.