Construction of sp2/sp3 Hybrid Carbon Thin Layers on Silicon Substrates Using Nonequilibrium Excitation Reaction Fields.

The authors have developed a crystal growth process that utilizes electron beams from field emission (FE) to grow materials bottom-up by a method other than the transfer of thermal energy. In this study, highly crystalline single-walled carbon nanotubes were used as a field emission electron source. Electron beams with high resolution energy emitted from the source were irradiated onto acetylene gas as a nonequilibrium reaction field to induce acetylene dissociation. The generated carbon ions were then irradiated onto a [100] silicon substrate, resulting in the irradiation of the silicon substrate surface with graphene. Moreover, the crystal growth of sp2/sp3 hybrid carbon thin layers, which is different from the crystal structures of graphite, diamond, and diamond-like carbon, proceeded on the surface of the silicon substrate. Carbon layers on periodic crystal structures whose growth depends at least on the morphology of the substrate are formed through bridging with the binding site of the substrate. The authors have succeeded in developing a nonthermal technique of crystal bridging between different elements. The substrate on which the carbon layer is formed is not limited to silicon; other substrates with various crystal structures and periodicities are expected to be used.