Local valence band densities of states of Al sub x Ga sub (1-x) As.

Aluminum L sub (2,3) soft x-ray emission (SXE) spectra measured for Al sub x Ga sub (1-x) As in the range (00.8) show changes due to modifications of the s-like local density of states (DOS) as the Al concentration is varied from x=0.05 to x=0. 8. Differences in SXE data and x-ray photoemission spectra with alloy composition are attributed to the difference between the local DOS measured by SXE spectroscopy and the global DOS measured by photoemission spectroscopy. These measurements show a non-linear shift of the top of the valence band and slope change near x=0.4 may be explained in part by the role of cation d-orbitals and other hybridization effects which correlate with the direct-indirect bandgap transition.