Picosecond surface restricted grating studies of n-GaAs(100) liquid junctions. Evidence for interfacial charge transfer approaching adiabatic limits

Abstract

In situ grating studies of n-GaAs/1 M KOH (Se2−/1−) aqueous liquid contacts have observed 1–2 picosecond decay components in the presence of the selenium redox couple. Based on the bias and concentration dependencies of the grating signal, and known hole scavenging properties of Se2−, the fast initial decay is assigned to interfacial hole transfer. The similarity in time scales between charge transfer and the diffusive component to the solvent relaxation along the reaction coordinate at the Helmholtz double layer indicates the electronic coupling at the interface is near the strong coupling limit.