Chirality effect of single-wall carbon nanotubes on field emission

The chirality effect of an opened-end single-wall carbon nanotube on field emission is studied by using the tunneling theory with the tight-binding approximation. The characteristic of the emission-current line density versus field is found to be dependence on the chirality of nanotubes. A metallic tube has a line density higher than that of a semiconducting one. Also, for semiconducting tubes, a tube of larger chiral angle has a line density higher than that of smaller chiral angle; a zigzag semiconducting tube has a smallest line density among the others. Further, the Fowler-Nordheim plots may have a nonlinear behavior in high current region. Finally, at temperature T<1000 K, the emission current is almost independent of temperature. Our results are explained by the energy band structure of nanotubes. (C) 2003 American Institute of Physics.