The Effect of Oxygen Molecule Adsorption on Structural and Electrical Properties of (8, 0) Carbon Nanotube: A Density Functional Study

By using spin polarized density functional calculations, we investigate the effect of oxygen molecule adsorption on the structural and electrical properties of (8, 0) single wall carbon nanotube. The obtained results indicate endothermic chemisorption of O2on the nanotube surface with a large binding energy of about 598 meV and a significant charge transfer of about 0.43 e-per molecule. We find that despite the triplet ground state configuration of free oxygen molecule, adsorbed oxygen on the nanotube prefers a zero moment spin singlet state. It is discussed that O2chemisorption dopes the (8, 0) carbon nanotube with hole carries and thus increases its work function from 4.34 to 4.89eV. This hole doping effect may show potential applications of carbon nanotubes in conductivity and thermopower electric based sensors.