Carbon nanostructures have been gaining considerable interest after the discovery of fullerenes in 1985 showed the possibility of stable curvatures of carbon forms. The large surface areas and porosities of the carbon nanostructures also helped their applications in energy production, storage, and transmission. Also, carbon nanotubes (CNTs) in layered transition metal oxides are very attractive materials for high-energy-density supercapacitor applications. The dominant mechanism for defect creation on CNTs by irradiation of charged particles is the knock-on atomic displacement due to kinetic energy transfer. Controlled modifications of carbon nanostructures such as multiwalled carbon nanotube (MWCNT) and graphene can be used in applications such as supercapacitors and field emission displays. Conventional chemical vapor deposition synthesis of MWCNT samples was carried out at 750°C using iron on silicon substrates for the first set of experiments. The decrease of capacitance at higher doses is attributed to the amorphization of MWCNTs, which lowers the conductivity of nanotubes.
