Formation of large area closely packed carbon onions film by plasma-based ion implantation

A substantial quantity of carbon onions in a durable film state is indispensable for its applications. In this study, large area fabrication of closely packed homogeneous carbon onion nanoparticle film using plasma-based ion implantation was demonstrated. Ag film deposited on a Si substrate was used as the implantation target for the hydrocarbon ions accelerated at 20 kV. Nanoparticles with the mean diameter of 7.5 nm were formed at the grain boundary of the Ag film. Carbon onions with the mean diameter of 17.4 nm were synthesized and arranged to a closely packed nanoparticle film with the thickness of around 200 nm by gradual thermal vaporization of the Ag. The closely packed configuration was achieved due to the isolated growth of carbon onion nanoparticle and high uniformity of the diameter. This process can be used in principle large area formation compered to typical ion implantation technique of carbon onion nanoparticle film, which can be applicable for the practical use in mechanical and electrochemical applications.