Atomic and electronic structures and energetics of the pyridine-type defects in nitrogen-doped carbon nanotubes were investigated using first-principles density-functional calculations. To discuss the stability of pyridine-type configurations, the total energies of the possible nitrogen formations in the nitrogen-doped (10,0) carbon nanotube were calculated. From the results of total-energy calculations, it was found that the pyridine-type defects in the nitrogen-doped (10,0) carbon nanotube was energetically preferred to the substitutional nitrogen defects under the existence of the vacancy in the nanotube. Also considered were the impurity states induced by the pyridine-type configurations in the nitrogen-doped nanotube.

Energetics and Electronic Structures of Pyridine-Type Defects in Nitrogen-Doped Carbon Nanotubes. Y.Fujimoto, S.Saito: Physica E, 2011, 43[3], 677-80