The properties of a GaAs–oxide interface formed by recently proposed photochemical oxidation in water were studied. Remarkable photoluminescence intensity enhancement was observed after oxidation which previously was interpreted as “unpinning” of the Fermi level. However, the surface current transport and capacitance-voltage measurements consistently indicated a strong Fermi level pinning with an increased surface depletion. These apparently contradictory results can be explained by a new model in which photochemical oxidation does not unpin, but shifts the pinning position of the Fermi level towards the valence band edge.
ASJC Scopus subject areas
- Physics and Astronomy(all)