THE ELECTROCHEMISTRY OF INP IN AQUEOUS K3CR(CN)6 SOLUTION

The electrochemical reactions of the redox couple Cr(CN)63-/4- at n- and p-type GaAs and InP electrodes were studied in detail. At GaAs electrodes, Cr(CN)63- is reduced by electrons from the conduction band while Cr(CN)64- is oxidized by hole capture from the valence band. At InP, on the other hand, both processes take place via the CB. At p-InP, electrons injected into the CB by Cr(CN)64-recombine with VB holes, resulting in light emission. This is the first observation of anodic electroluminescence with a simple redox system. The photocurrent-potential curve at p-InP in a K3Cr(CN)6 solution was investigated. Simulations, based on a model presented here, provide an explanation for the presence of an additional rotation rate dependent plateau in the photocurrent-potential curve.