Surface functionalization of few-layer graphene on β-SiC(001) by Neutral Red dye

Few-layer graphene on beta-SiC(001) functionalized with phenazine dye Neutral Red by means of diazonium chemistry has been studied using X-ray photoelectron spectroscopy, near-edge X-ray absorption fine structure, photoemission electron microscopy, scanning tunneling microscopy, and density functional theory calculations. The experimental data reveal the formation of a composite phenazine dye/graphene structure with a large energy gap. The molecules in this structure can be oriented both parallel and perpendicular to the graphene surface. According to scanning tunneling spectroscopy and theoretical calculations, the density of electron states in different surface areas depends on the local short-range order and the molecules' environment. On the other hand, the photoemission spectroscopy study shows that the bottom layers of the few-layer graphene remain intact, which inherently makes the synthesized layered composite a low-dimensional metal/semiconductor heterostructure. In addition, photoemission electron microscopy imaging shows a high homogeneity of the dye-modified graphene on a micrometer scale.

Automated summary

This study investigates the functionalization of few-layer graphene on beta-SiC(001) with phenazine dye Neutral Red using diazonium chemistry. Various techniques and theoretical calculations were employed to analyze the composite structure and properties. The experimental results reveal the formation of a composite structure with a large energy gap, where the molecules can be oriented both parallel and perpendicular to the graphene surface. The study also shows the intact bottom layers of few-layer graphene, resulting in a low-dimensional metal/semiconductor heterostructure.