Computational and experimental studies of graphene and carbon nanotubes

Abstract

Bilayer graphene and single-walled carbon nanotubes were studied through classical molecular dynamics using Tersoff potential. The Tersoff potential has been the most successful model to replicate much of the semiconducting properties in carbon structures. The simulations were performed within a canonical (NVT) ensemble for structural properties and isothermal–isobaric ensemble (NPT) for thermodynamic properties of both materials. The bilayer graphene consists of two models of 64 and 256 atoms. Single-walled carbon nanotubes consist of three chiral structures of 264 atoms which is cnt(12,10), 260 atoms which is cnt(10,12) and armchair structure of 312 atoms which is cnt(12,12). The structural and thermodynamics properties were investigated in a range of temperature from 300 - 5000 K. It has been found that some of the properties of the graphene and carbon nanotube are similar. Graphene256 was found to be more stable than graphene64 and the armchair cnt(12,12) appears to be more mechanically stable than chiral cnt(12,10). Graphene and single-walled carbon nanotubes were also studied using X-ray diffraction and atomic force microscopy (AFM). The lattice constant for both materials were calculated and they agree well with the computational results. For carbon nanotubes, different solvents were used for characterization using the AFM. Chloroform was the best solvent since we managed to find some bundles of carbon nanotube. For ethanol and toluene solvents we did not managed to get any bundles. The diameter of single-walled carbon nanotube was determined only on a solution that chloroform solvent was used.