Vertically Aligned Carbon Nanotube Microbundle Arrays for Field-Emission Applications

The fabrication, properties, and applications of vertically aligned carbon nanotube (VACNT) microbundle arrays with different length-to-diameter ratios were investigated. VACNT microbundle arrays with different length-to-diameter ratios from 4:1 to 30:1 and microscaling of carbon nanotube blocks were fabricated using pulsed laser ablation technology. These VACNT microbundle arrays had a very low threshold field (0.117 V/μm), excellent time stability, and high field emission current densities (137.91 A/cm2). These values are superior to those of carbon nanotubes grown directly on a silicon substrate. The large length-to-diameter ratio and the small diameter of the VACNT microbundles are considered to be the main reasons for the excellent field emission performance.