Electronic structure, optical and structural properties of Si, Ni, B and N-doped a carbon nanotube: DFT study

The electronic structure, structural and optical properties of a carbon nanotube (CNT) and silicon (Si), nickel (Ni), boron (B) and nitrogen (N)-doped CNTs have been investigated by density functional theory (DFT) simulations. We present a comparative analysis to demonstrate how the dopant atoms interact with a CNT. The geometrical properties, lowest harmonic frequency, total energy, dipole moment, Mulliken atomic charges, formation energy, HOMO-LUMO gap, optical refractive index and density of state spectra are analyzed using DFT. The optical absorption spectra are also researched based on TD-DFT method. The bond distances and the corresponding properties exhibit remarkable variations based on the type of the dopant atom. Si and Ni atoms was found to considerably reduce the band gap of CNT. The effect of dopant atoms is quite pronounced in enhancing the electronic and optical absorbance properties of the pure CNT. Our results suggest that a dopant atom has different effect on the pure CNT and it may have potential in designing new electronic devices.