The Synthesis of NiO/TiO2Heterostructures and Their Valence Band Offset Determination

In this work, a heterojunction based on p-type NiO/n-type TiO2nanostructures has been prepared on the fluorine doped tin oxide (FTO) glass substrate by hydrothermal method. Scanning electron microscopy (SEM) and X-Ray diffraction techniques were used for the morphological and crystalline arrays characterization. The X-ray photoelectron spectroscopy was employed to determine the valence-band offset (VBO) of the NiO/TiO2heterojunction prepared on FTO glass substrate. The core levels of Ni 2p and Ti 2p were utilized to align the valence-band offset of p-type NiO/n-type TiO2heterojunction. The valence band offset was found to be∼0.41 eV and the conduction band was calculated about∼0.91 eV. The ratio of conduction band offset and the valence-band offset was found to be 2.21.