Structure design and properties investigation of Bi2O2Se/graphene van der Waals heterojunction from first-principles study

The related structural design of Bi2O2Se/graphene van der Waals heterojunction, by changing the layer interfacial distance, the binding surface and the stacked layers have been systematically investigated by using the first-principle calculations with the on-site Hubbard Ueff (Ueff = 2.5 eV) parameter (GGA+U). The geometric and energy characteristics of the systems are calculated, and the dependence of the structural parameters, as well as the band structure and density of electronic states, the two preferred structures are finally determined. That is, the layer interfacial distance is 3.2 and 3.4 A of GS-TL structure (G is Graphene, S is Se atomic layer, T is Two, and L is layer. GS means graphene combined with Se atomic layer. TL means Bi2O2Se is two layers.), respectively. In GS-TL structure, a very narrow band gap opens (0.015-0.027 eV). Electronic structure analysis shows that the graphene makes the hybridization of s-orbital and p-orbital stronger between -8 and 0 eV, thus narrowing the band gap of Bi2O2Se. Furthermore, from the light absorption, reflection, energy loss, complex refractive index, complex dielectric function, photoconductivity, and other six points of view analysis, it can be seen that Bi2O2Se/ graphene heterojunction (GS-TL structure with the layer interfacial distance of 3.2 and 3.4 A) reaction range of light is larger, increasing the detection ability of long wave light (0 similar to 2 eV), its application in photoelectric detectors has a great prospect.