High density carbon nanotube growth using a plasma pretreated catalyst

We have developed a direct current plasma pretreatment of the Fe catalyst to increase the area density of vertically-aligned carbon nanotube forests. The carbon wall density of the double- and multi-walled nanotubes reaches 4.8 × 1012 cm−2, with a 40% volume occupancy and a mass density of ∼0.4 g cm−3. The plasma pretreatment works by reducing the sintering of the catalyst nanoparticles during growth. This treatment increases the forest density by 8 times compared to the standard growth conditions.