Syntheses of carbon nanomaterials by radio frequency plasma enhanced chemical vapor deposition

We report a simple and effective method for syntheses of carbon nanomaterials, including a hybrid CNTs/cobalt particles shelled with graphitic layers, pure CNTs, a CNTs/carbon nanosheets (CNSs) composite and pure CNSs, on O-2-thermal etched Co substrate films, in discharging different mixed gases (CH4/H-2, CH4/H-2/O-2, CH4/Ar and CH4/Ar/O-2. respectively), using radio frequency plasma enhanced chemical vapor deposition (PECVD). Being etched by O-2 during the pretreatment stage, Co thin film transformed into small CoO particles and consequently the deoxidization of CoO particles may occur in PECVD process when different reactive gases are used to obtain various carbon nanomaterials. We find that the reactive gases govern the degree of how the CoO particles can be deoxidized and determine the final carbon nanomaterial products. In this work, the possible growth mechanisms for obtaining various carbon nanomaterials have been explored. (C) 2009 Elsevier B.V. All rights reserved.