Rapid growth of well-aligned carbon nanotube arrays

Vertically aligned carbon nanotube (CNT) arrays with high density were synthesized on quartz substrates in large areas (100×40 mm2) by catalytic decomposition of a ferrocene–xylene mixture at 850 °C in a quartz tube reactor. The nanotubes grow at a high growth rate of ∼50 μm/min, and reach 1.5 mm in length in 30 min. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) investigations reveal that the nanotubes are high-purity multi-wall CNTs with well-ordered graphene sheets, and about 30–60 nm in diameter. This provides a simple way to synthesize well-aligned CNTs in large areas. A continuous rapid growth model is suggested for the CNTs in high growth rate under our experimental conditions.