Features of the atomic structure and electronic properties of hybrid films formed by single-walled carbon nanotubes and bilayer graphene

Background and Objectives: The combination of carbon nanotubes and graphene opens up wide opportunities for the production of nanomaterials with customizable properties and their application in the development of the element base of nanoelectronic devices. To control the properties of hybrid structures formed by graphene and nanotubes, it is important to understand the regularities of physical processes in them at the atomic level. Methods of computer modeling are an effective tool for solving this problem. The purpose of research is to identify the regularities of the influence of the atomic structure features on the electronic properties of hybrid films formed by bilayer graphene and single-walled carbon nanotube of various topologies. Materials and Methods: Energetically stable supercells of four atomic configurations of graphene-nanotube hybrid films were constructed on the basis of nanotubes (5,5), (6,0), (12,6) and (16,0). The analysis of the band structure and distribution of the density of electronic states was carried out for the constructed supercells using a density functional based tight binding method. Results: It has been revealed that the graphene-(5,5) and graphene-(16,0) configurations have a metallic type of conductivity, while the graphene-(6,0) and graphene-(12,6) configurations are characterized by the presence energy gap between the valence band and the conduction band. It has been found that nanotubes play a decisive role in the formation of the density of states profile of hybrid films. The key factor in determining the type of conductivity of hybrid films is the mutual orientation of nanotubes and graphene in the composition of the film. Conclusion: Thus, by varying the chirality of nanotubes and the method of their arrangement relative to graphene, one can control the electronic properties of hybrid graphene-nanotube films.