Measurement of the valence-band offset at the epitaxial MgO-GaAs(001) heterojunction by x-ray photoelectron spectroscopy -: art. no. 042108

The electronic band structure at the interface of the MgO-GaAs(001) tunnel contact has been experimentally studied. X-ray photoelectron spectroscopy has been used to measure the valence-band offset at the MgO-GaAs(001) heterojunction interface. The valence-band offset Delta E-V is determined to be 4.2 +/- 0.1 eV. As a consequence, a nested type-I band alignment with a conduction-band offset of Delta E-C=2.2 +/- 0.1 eV is found. The accurate determination of the valence and conduction band offsets is important for the fundamental understanding of the tunnel spin injection in GaAs. (c) 2006 American Institute of Physics.