Valence band offset of Cu2O/In2O3 heterojunction determined by X-ray photoelectron spectroscopy.

In2O3 is a promising partner of Cu2O to form a Cu2O/In2O3 heterojunction system. We used x-ray photoelectron spectroscopy to determine the valence band offset (VBO) of a Cu2O/In2O3 heterojunction. The valence band offset is found to be 1.43 ± 0.2 eV. Given the experimental bandgaps of 2.0 eV and 2.6 eV for Cu2O and In2O3, respectively, we calculate the band alignment of a Cu2O/In2O3 heterojunction with a conduction band offset (CBO) of 0.83 ± 0.2 eV. To apply Cu2O/In2O3 bilayers in electronic devices, it is important to determine the band alignment accurately based on the VBO and CBO. [ABSTRACT FROM AUTHOR]