Valence band offset of ZnO/Zn0.85Mg0.15O heterojunction measured by x-ray photoelectron spectroscopy

X-ray photoelectron spectroscopy was used to measure the valence band offset at the ZnO/Zn0.85Mg0.15O heterojunction grown by plasma-assisted molecular beam epitaxy. The valence band offset (ΔEV) is determined to be 0.13 eV. According to the experimental band gap of 3.68 eV for the Zn0.85Mg0.15O, the conduction band offset (ΔEC) in this system was calculated to be 0.18 eV. The ΔEc:ΔEv in ZnO/Zn0.85Mg0.15O heterojunction was estimated to be 3:2.