Growth of high-density parallel arrays of ultralong carbon nanotubes with catalysts pinned by silica nanospheres

High-density parallel arrays of ultralong carbon nanotubes (CNTs) were prepared by utilizing catalyst nanoparticles anchored by silica nanospheres through chemical vapor deposition (CVD). Silica nanospheres and catalyst solution were sequentially spin-coated onto the substrates for the growth of ultralong CNTs, followed by annealing to remove the polymer residues. Catalyst nanoparticles can be anchored on the top of or around the silica nanospheres. Then, ultralong CNTs were synthesized with methane as the carbon source at 1010 °C under ambient pressure. Our results show that the areal density of the ultralong CNTs produced by this nanosphere-assisted process was obviously improved compared with that by the typical process without nanospheres.