Field-emission properties of aligned carbon nanotubes

Dense, well-separated, and aligned carbon nanotubes have been prepared via bias-enhanced microwave plasma chemical vapor deposition. The turn-on field s defined at the emission current density of 10 mu A/cm(2) are about 3.35 V /mu m, 2.54 V/mu m, and 3.54V/mu m, for the immersion times in PdCl2 of 1 m in, 20 min, and 40 min,respectively. The corresponding emission current den sities are about 0.97 mA/cm(2), 4.5 mA/cm(2), and 0.44 mA/cm(2) at the elec tric field of 5 V/mu m. The higher emission current obtained from the align ed carbon nanotubes for the immersion time of 20 min is ascribed to the den ser and sharper nanotubes formed in this condition.