Effect of oxygen chemisorption on the energy band gap of a chiral semiconducting single-walled carbon nanotube

We present a detailed investigation of the effect of oxygen chemisorption on the band gap of both a zigzag (10,0) and a chiral (8,4) single-walled carbon nanotube (SWNT) by means of density functional theory (DFT). The chemisorption of an oxygen atom leads to the formation of epoxy or ether structures in several possible sites of the outer wall. In the (10,0) nanotube, oxidation at the two possible sites drastically decreases the energy band gap. In the chiral (8,4) nanotube, the band gap remains almost constant upon oxidation at two of the three available sites and decreases considerably for the third site.