Synthesis and characterization of carbon nanoparticle films prepared by plasma-based ion implantation

Carbon nanoparticles (CNPs) were synthesized by the plasma-based ion implantation method, and structural variations and the synthesis mechanism of CNPs were investigated. CNPs were grown by implanting carbon ions from methane gas into thin silver films. To obtain pure CNPs from the silver matrix, the silver films were evaporated by a thermal process under high vacuum. XPS depth analysis revealed that initially silver atoms were preferably sputtered during implantation, then CNPs gradually started to appear on the silver and carbon atoms concentrated near the surface. Stacked carbons on the surface may prevent silver films from being sputtered and carbon ions from penetrating into the silver matrix. The CNPs grew up to 20 nm, but their size did not increase after the implantation for 2 h. Instead, a membrane cluster among the CNPs was observed after the implantation for 3 h. Thermal process at 750 degrees C for removing silver to obtain only CNPs did not affect CNP growth. Raman spectra indicated that spherical CNPs consist of graphitic structure and long-time implantation yielded amorphous membranes as well as the CNPs. Copyright (C) 2014 John Wiley & Sons, Ltd.