Electronic properties of single-wall carbon nanotubes and their dependence on synthetic methods

Since their discovery in 1991, carbon nanotubes have been intensively studied, and a number of new applications have been identified. Applications range from nanoelectronics to hydrogen absorption for battery electrodes and fuel cells. Because of their high electrical conductivity and strength, high sensitivity atomic force microscopes already use carbon nanotubes for their tips, and carbon nanostructures are also used as electron beam emitters for medical and scientific equipment. Electron emission is directly correlated with the work function and the ionization potential of carbon nanotubes. Gaussian 98 software was used to perform theoretical quantum calculations on a limited set of HyperChem 5.01 simulated metallic single-wall carbon nanotubes. These initial sets of calculations show that bandgaps and work functions of these small carbon nanostructures are dependent upon the diameter of the tubes, and to a lesser degree so is the ionization potential. In addition, we demonstrate how the manufacturing methods can directly affect the diameter of the nanotubes produced, and therefore directly influence the electrical properties of the nanotubes.