Scanning field emission from patterned carbon nanotube films

The investigation of the field emission (FE) properties of carbon nanotube (CNT) films by a scanning anode FE apparatus, reveals a strong dependence o n the density and morphology of the CNT deposit. Large differences between the microscopic and macroscopic current and emission site densities are obs erved, and explained in terms of a variation of the field enhancement facto r beta. As a consequence, the emitted current density can be optimized by t uning the density of CNTs. Films with medium densities (on the order of 10( 7) emitters/cm(2), according to electrostatic calculations) show the highes t emitted current densities. (C) 2000 American Institute of Physics. [S0003 -6951(00)00815-9].