The energy band alignment at the interface between mechanically exfoliated few-layer NiPS3 nanosheets and ZnO

•We fabricated few-layer NiPS3 nanosheets on ZnO/Nb:SrTiO3 by mechanical exfoliation method.•Insertion of ZnO layer enhances visibility of few-layer NiPS3 and prevents charging effects for photoemission studies.•The band offset of NiPS3/ZnO is determined using micro-beam XPS measurements.•Type-II band alignment is observed at the interface of NiPS3 and ZnO.•The values of valence band offset increase as NiPS3 layer number decreases.

We have studied the electronic structure and interfacial properties of mechanically exfoliated few-layer NiPS3 van der Waals crystals on ZnO/Nb:SrTiO3 substrates using scanning photoelectron microscopy and spectroscopy. The conducting ZnO layer enhances the visibility of few-layer NiPS3 on Nb:SrTiO3 and prevents charging effects in photoemission. We experimentally determined a type-II band alignment at the NiPS3/ZnO interface. The valence band offset (VBO) of few-layer NiPS3/ZnO is 2.8 ± 0.09 eV, and the conduction band offset is 1.0 ± 0.09 eV. Moreover, we found an increase of ∼0.3 eV in VBO as decreasing NiPS3 thickness, suggesting electronic coupling or charge transfer at the NiPS3/ZnO interface.

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