Valence-band offset of epitaxial ZnOMgO (111) heterojunction determined by x-ray photoelectron spectroscopy

Abstract

The valence-band offset of ZnOMgO (111) heterojunction has been directly measured by x-ray photoelectron spectroscopy. Excluding the strain effect, the valence-band offset is determined to be 0.87±0.20 eV, and the conduction-band offset Δ EC is deduced to be -3.59±0.20 eV, indicating that ZnOMgO heterojunction has a type-I band alignment. The conduction-band and valence-band offset of MgOZnO is used to interpret the origination of p -type conduction in undoped Mgx Zn1-x O alloy and deeper acceptor level in undoped and N-doped p -type Mgx Zn1-x O alloy than in ZnO. © 2008 American Institute of Physics.