Investigation of Doping Effects and Defects in Chiral Carbon Nanotubes

Carbon nanotubes are allotropes of carbon and are 1D nanomaterials with various applications, including their use as sensors, in composites, and even as drug delivery vectors. In this study, we employed density functional theory with a local density approximation, implemented in the SIESTA software, to analyze the electrical properties of the chiral (6,3) carbon nanotube containing 48 carbon atoms. We performed studies on energy bands and total and partial density of states. Systems doped with Boron and Nitrogen were investigated, as well as simulations of defects (vacancies). Our results indicate that the nanotube exhibits semiconducting behavior with a bandgap of 0.115 eV. However, after the inclusion of Nitrogen, Boron, and vacancy impurities, its character changes to metallic, with energy bands crossing the Fermi level. The density of states analysis revealed that the carbon 2p orbitals contribute the most to charge mobility compared to the 2p orbitals of Boron and Nitrogen, and al