The controlled growth of horizontally aligned single-walled carbon nanotube arrays by a gas flow process

High-density horizontally aligned single-walled carbon nanotubes (SWCNTs) have been grown by annealing Fe catalyst in air and optimizing catalyst thickness in the gas flow process. The aligned SWCNT density reaches >60 nanotubes per 100 μm and the length can be a few millimeters. Interestingly, the growth of aligned SWCNT arrays can be extended from the catalyst substrate to a downstream substrate across the gap between them by gas flow when the two substrates are put close to each other, and thus an aligned SWCNT array has been achieved on an isolated clean substrate.