Control of crystalline and electronic structures of carbon nanowalls for their device applications

Controlling factors of crystalline and electronic structures of carbon nanowalls were investigated in this study. Precise measurements and controls of radicals and ions in the plasma make the controlled syntheses of CNWs possible. For example, density ratios of hydrogen (H) and carbon atoms are essential to determine the density and height of CNWs. Ar⁺ ion irradiation is also important for vertical-growth of graphene sheets. Vertical-growth of graphene sheets could occur only under Ar⁺ ion irradiation with suitable energy and flux for each process. On the other hand, by N₂ gas addition to C₂F₆/H₂/Ar mixture ambient, the CNWs with n-type conducting properties can be formed. These results obtained in this study suggest that the CNWs are promising as new functional device materials in various applications.