Using density-functional theory calculations, an investigation was made of how the stabilities and electronic properties of Stone Wales defective armchair (4,4) and (5,5) nanotubes were modified via Si atom doping at eight selected symmetric positions of Stone-Wales defect sites with two different orientations, parallel and diagonal. A quasi-tetrahedral bonding configurations of silicon atoms based on sp3 hybridization were formed, which led to puckered silicon doped rings. The results indicated that tube diameter affects the doping reactions so that the doping single-walled carbon nanotubes with high curvature (small diameter) might be more favorable, based on both energetic and structural considerations. Density of state obtained for the systems indicate that the doping of the defect sites causes the redistribution of electronic states of the SW defective single-walled carbon nanotubes. An average charge of 0.5e was also transferred from silicon atoms to first neighboring carbon atoms on the single-walled carbon nanotube, which indicates that charge redistributions after doping process mostly take place to a relatively small number of carbons at the zone of doped atoms.

Silicon Doping of Defect Sites in Stone-Wales Defective Carbon Nanotubes: a Density Functional Theory Study. M.Anafcheh, R.Ghafouri: Superlattices and Microstructures, 2013, 60, 1-9