Determination of band alignment in two-dimensional h-BN/WS2 van der waals heterojunction by X-ray photoelectron spectroscopy

Abstract We have fabricated two-dimensional h-BN/WS2 van der Waals heterojunctions by stacking h-BN and WS2 monolayers, and experimentally measured the valence band offset (VBO) of h-BN/WS2 heterojunction by X-ray photoelectron spectroscopy (XPS). The h-BN and WS2 monolayers band gaps and the measured value of VBO were used to determine the conduction band offset (CBO). The measurement results of VBO and CBO are 3.39 ± 0.15 eV and 0.57 ± 0.15 eV, respectively, revealing a type-I band alignment. It is urgent to measure the band alignment parameters of h-BN/WS2 heterojunctions for analyzing and designing h-BN/WS2 based devices.