Schematics of spark discharge process and patterned growth of CNTs with different densities. (a) Schematic of nanoparticle generation and deposition process. Aerosol nanoparticles were generated by spark discharge and passed onto the cooled substrate sitting on the Peltier cooler. In the aerosol, small nanoparticles moved to the substrate because of the thermophoresis effect and were deposited through a hole in the patterned mask. The quantity of deposited nanoparticles is proportional to the deposition time. (b) A short deposition time leads to low-density CNTs. (c) After enough deposition time, vertically aligned CNTs grow.
Na et al. Nanoscale Research Letters 2013 8:409 doi:10.1186/1556-276X-8-409