GaSb/GaAs quantum dot systems: in situ synchrotron radiation x-ray photoelectron spectroscopy study

In English GaSb/GaAs quantum dot systems are fabricated using MBE under various growth modes. The as-grown samples are studied with in situ synchrotron radiation XPS covering the As 3d, Sb 4d and Ga 3d core levels and the valence band region. The XPS spectra show dramatic changes with the growth modes, reflecting changes in the local electronic structure and chemical environments of the surface and interface atoms in both quantum dots and wetting layer. A quantum dot specific contribution near the valence band maximum is identified and related to the hole accumulation process. Local valence band offsets measured in the GaSb/GaAs systems evolve over the interface region and depend on the growth modes, which adds another degree of freedom to band engineering on the nanoscale.