Articles you may be interested inSimple model of bulk and surface excitation effects to inelastic scattering in low-energy electron beam irradiation of multi-walled carbon nanotubes Study of geometrical effects on the characteristics of metallic double-walled carbon nanotube waveguides through quantum hydrodynamics Phys. Plasmas 16, 063501 (2009); 10.1063/1.3142468
Carrier density and quantum capacitance for semiconducting carbon nanotubesWe have conducted calculations of the collective plasmon excitations for an electron gas confined to the surface of a charged single-walled cylindrical nanotube in salt solutions. Both positively and negatively charged nanotubes are investigated. At high salt concentration, the surface potential approaches zero, and the spectrum is close to that of a neutral nanotube. The highest-frequency branch of the plasmon excitation spectrum exhibits a redshift and a blueshift for negatively and positively charged nanotubes, respectively. Such a result can be attributed to the change of the number of eigenstates around the Fermi energy. As salt concentration is increased, the surface potential is screened out, and the spectral line shift diminishes. Our results also show that the negatively charged nanotube can be more sensitive to the ambient salt concentration than the positively charged one. The optimal sensor device occurs when the nanotube carries a linear charge density close to that of DNA. The theoretical predictions suggest that charged nanotubes have the potential as sensors to probe salt concentration.