  A set of LaAlO3/SrTiO3 (LAO-STO) interfaces has been probed by X-ray
photoemission spectroscopy in order to contrast and compare the effects of LAO
overlayer thickness and of the growth conditions on the electronic properties
of these heterostructures. These effects are tracked by considering the
band-offset and the density of Ti3+ states, respectively. It is shown that the
dominant effects on the local electronic properties are determined by the O2
partial pressure during the growth. In particular, a low P(O2) yields Ti3+
states with higher density and lower binding energy as compared to the sample
grown at high P(O2) or to the bare STO reference sample. Band offset effects
are all below about 0.7 eV, but a careful analysis of Ti 2p and Sr 3d peaks
shows that valence band offsets can be at the origin of the observed peak
width. In particular, the largest offset is shown by the conducting sample,
that displays the largest Ti 2p and Sr 3d peak widths.
