Figure 1: Schematic illustration of the VPE process for chirality-controlled SWCNT synthesis.
From: Chirality-controlled synthesis of single-wall carbon nanotubes using vapour-phase epitaxy

The chirality-pure nanotube seeds obtained from DNA-based separation are first deposited onto various kinds of substrates, including quartz and Si/SiO2, followed by air annealing and water vapour annealing processes to activate the ends for the ensuing VPE growth. VPE with either methane or ethanol as the carbon feed stock is then used to achieve chirality-controlled growth from these seeds.