Band alignment of ZnO/ZnS heterojunction prepared through magnetron sputtering and measured by X-ray photoelectron spectroscopy

In this study, three film samples (ZnO, ZnS and ZnO/ZnS heterojunction) were prepared by a facile magnet sputtering deposition method. All the films exhibited the good crystal quality and smooth surface. Further, the X-ray photoelectron spectroscopy (XPS) was employed to examine the band offset between ZnO and ZnS layers at the interface. It was demonstrated that the ZnO/ZnS bilayers exhibited a II-type band alignment with a valence-band (VB) offset of 1.04 eV, which was accordance with the calculation results. It thus suggested that such a heterostructure was suitable for application as a photocatalyst or photoanode for water splitting or photoelectric conversion.