Field-Emission Properties of Aligned Carbon Nanotubes

Abstract

Dense, well-separated, and aligned carbon nanotubes have been prepared via bias-enhanced microwave plasma chemical vapor deposition. The turn-on fields defined at the emission current density of 10 µA/cm² are about 3.35 V/µm, 2.54 V/µm, and 3.54 V/µm, for the immersion times in PdCl₂ of 1 min, 20 min, and 40 min, respectively. The corresponding emission current densities are about 0.97 mA/cm², 4.5 mA/cm², and 0.44 mA/cm² at the electric field of 5 V/µm. The higher emission current obtained from the aligned carbon nanotubes for the immersion time of 20 min is ascribed to the denser and sharper nanotubes formed in this condition.