First-principles calculations were used to investigate the influence of alkali metal (Li/Na/Cs) adsorption and defect position upon the work function of a (5,5) armchair single-walled carbon nanotube with a capped edge. Atomic Cs adsorption could more effectively reduce the work function of the carbon nanotube than could atomic Li/Na adsorption. The adsorption position had a measurable impact upon the work function of the carbon nanotube. Any vacancy defect on the tip could raise the work function of the carbon nanotube regardless of whether or not an alkali metal atom was absorbed. The variations in work functions were attributed mainly to the change in Fermi levels induced by charge redistributions. The alkali metal adsorption could also transform the semiconducting carbon nanotube into a metallic tube.

Role of Alkali Metal Adsorption and Defect Position on the Work Function of a (5, 5) Capped Single-Walled Carbon Nanotube. S.F.Xu, G.Yuan, C.Li, H.Mimura: Journal of Vacuum Science and Technology B, 2011, 29[4], 04E101