Dependence of alternating photocurrent on n-GaAs electrodes upon frequency and illumination intensity

Abstract

The photoinduced alternating current enhancement on semiconductor electrodes in the potential range between flatband and stationary photocurrent onset has been investigated on n-GaAs, taking into consideration the dependences upon frequency and illumination intensity. The alternating photocurrent peak at the onset potential turned out to be nearly frequency-independent, whereas the additional structure of the alternating photocurrent curve between the onset the flatband potential depended strongly on the frequency. These observations are in agreement with the predictions of charge transfer theory for the case of chemisorption of solute (particularly protolytic) species. The theory of chemisorption-controlled alternating photocurrent has been extended by considering partial charge transfer both over the valence and conduction band (fractional-hole and fractional-electron transfer). Peculiarities of a light-driven chemisorption state have been taken into account.