Tuning AlAs-GaAs Band Discontinuities and the Role of Si-Induced Local InterfaceDipoles

摘要

The presence of thin ordered layers of Si within the interface regions of AlAs-GaAs heterostructures is found to tune the valence band offset throughout the 0.02-0.78 eV range. High resolution X-ray photoemission studies of heterostructures prepared in situ by molecular beam epitaxy as a function of substrate temperature, arsenic flux, interface concentration of Si, and growth sequence (AlAs on GaAs versus GaAs on AlAs) indicate that this tunability is associated with a Si related local dipole which can be added to or subtracted from the intrinsic AlAs-GaAs valence band offset of 0.40 eV.