Analysis of photoluminescence experiments on p-type GaAs electrodes using a drift-diffusion model - art. no. 045326

We report an analysis of time-resolved photoluminescence from capped p-type GaAs in contact with solutions of cobaltocenium in acetonitrile in the pre sence of an externally applied potential. We use a drift-diffusion model to describe the dynamics of carriers in the semiconductor. We compare the res ults to experimental measurements which might qualitatively suggest a rapid electron-transfer rate from the GaAs to cobaltocenium ions in solution. Th e results show, however, that the experimentally observed decay in the phot oluminesce is dominated by the charge separation produced by the electric f ield, and the computed values of the electron-transfer velocity S-e, are qu ite small. The resulting S-e, is shown to have a slight dependence on the e xternal potential. This potential dependence is not significant enough to b e definitively established by the procedures described here. We discuss the usefulness of these methods to establish the existence of the injection of hot carriers into an electrolyte.