Abstract
X-ray photoelectron spectroscopy reinvestigation is done for the recently reported Si-interlayer-induced change of the valence band discontinuity (ΔEv) at GaAs-AlAs interfaces. The XPS measurements reproduced the large apparent change of ΔEv caused by the Si interlayer. However, it also led to anomalous increases of separations between the core level peak and the valence band edge as well as anomalous increases of full width at half maximum of the core level spectra. It is concluded that the observed change of ΔEv is only an apparent one. The anomalies were explained quantitatively by a new model based on the surface Fermi level pinning and interface delta-doping.