关键词: van der Waals heterojunction, x-ray photoelectron spectroscopy, band alignment, gallium nitride, platinum diselenide

Abstract: In order to investigate the effect of different doping types on the band alignment of heterojunctions, we prepared PtSe$_{2}$/n-GaN, PtSe$_{2}$/p-GaN, and PtSe$_{2}$/u-GaN heterojunctions by wet transfer technique. The valence band offsets (VBO) of the three heterojunctions were measured by x-ray photoelectron spectroscopy (XPS), while the PtSe$_{2}$/n-GaN is 3.70$\pm$0.15 eV, PtSe$_{2}$/p-GaN is 0.264$\pm$0.15 eV, and PtSe$_{2}$/u-GaN is 3.02$\pm$0.15 eV. The conduction band offset (CBO) of the three heterojunctions was calculated from the material bandgap and VBO, while the PtSe$_{2}$/n-GaN is 0.61$\pm$0.15 eV, PtSe$_{2}$/p-GaN is 2.83$\pm$0.15 eV, and PtSe$_{2}$/u-GaN is 0.07$\pm$0.15 eV. This signifies that both PtSe$_{2}$/u-GaN and PtSe$_{2}$/p-GaN exhibit type-I band alignment, but the PtSe$_{2}$/n-GaN heterojunction has type-III band alignment. This signifies that the band engineering of PtSe$_{2}$/GaN heterojunction can be achieved by manipulating the concentration and type of doping, which is significantly relevant for the advancement of related devices through the realization of band alignment and the modulation of the material properties of the PtSe$_{2}$/GaN heterojunction.

Key words: van der Waals heterojunction, x-ray photoelectron spectroscopy, band alignment, gallium nitride, platinum diselenide