Electronic and optoelectronic properties of van der Waals heterostructure based on graphene-like GaN, blue phosphorene, SiC, and ZnO: A first principles study

The combination of two-dimensional materials in the form of van der Waals heterostructures has been proved to be an effective approach for designing electronic and optoelectronic devices. In this work, we investigate the electronic, optical, and photocatalytic properties of vdW heterostructures based on BlueP, SiC, ZnO, and g-GaN using density functional theory. We find that all the g-GaN based vdW heterostructures are energetically and thermally stable at room temperature. The g-GaN-BlueP and g-GaN-SiC heterostructures show indirect bandgaps with the type-II and type-I band alignments, respectively, whereas the g-GaN-ZnO heterostructure shows a direct bandgap with type-II band alignment. Furthermore, the absorption coefficient is also calculated to understand the optical behavior of these hetrostructures. Our results demonstrate that the lowest energy transitions are dominated by excitons, and the blue shift is also observed in these hetrostructures. The g-GaN-BlueP, g-GaN-SiC, and g-GaN-ZnO vdW heterostructures possess outstanding optical absorption in the visible light. The g-GaN-P shows the highest absorption intensity of 10 5 cm - 1, which is larger than that of g-GaN-SiC and g-GaN-ZnO vdW heterostructures by three times. These findings demonstrate that these vdW heterostructures are promising candidates for water splitting in the visible light region. Moreover, the heterostructures also show good response to the photocatalytic properties at pH = 0 and pH = 7.