Pk. Schelling et Jw. Halley, Analysis of photoluminescence experiments on p-type GaAs electrodes using a drift-diffusion model - art. no. 045326, PHYS REV B, 6404(4), 2001, pp. 5326
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.