Plasma-CVD Enabling Seeded Growth of Nanocarbons from a Single Carbon-Nanoring

Enormous interest for applications ranging from electronics to therapeutics has been given to nanoscale carbon members (nanocarbons) with different dimensions such as 0D fullerenes, 1D carbon nanotubes, 2D graphene, 3D nanodiamonds due to their unique physical and chemical properties [1]. Here, one of the future challenges is considered to establish dimensional-fusion science and technology of the nanoscale materials, where fundamental studies on their synthesis such as exploring alternative/new methods for precisely structure-controlled, selective, impurity-free, composite, and architectural growth are of inevitable importance to follow a path toward the goal. In this light, we have strived to synthesize 1D single-walled carbon nanotubes (SWNTs), 2D graphene and graphene oxides (GO), and 3D vertical graphene (VG) by alcohol plasma-enhanced chemical vapor deposition (PECVD) without using metal catalysts regarded as impurities, where a single hoop of carbon six-membered rings (carbon nanoring: CNR) [2] is adopted as the seeded-growth molecule. Depending on the PECVD-parameter (growth-substrate temperature: T_sub, intensity of plasma influx to substrate: mild or harsh) region, it is found for the first time that the precisely structure(chirality)-controlled SWNT, GO, VG, and single-layer graphene grow for T_sub=350 ℃ / mild plasma, 700 ℃ / mild, 700 ℃ / harsh, and 1000 ℃ / harsh, respectively.  [1] R. Hatakeyama, Rev. Mod. Plasma Phys. 1, 7 (2017). [2] S. E. Lewis, Chem. Soc. Rev. 44, 2221 (2015).