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Two-dimensional Multiwalled Carbon Nanotube arrays (MWCNTs) were prepared by a novel high-density helicon wave plasma chemical vapor deposition (HWP-CVD) at room temperature. Preliminary studies show that the MWCNTs prepared by this method has strong orientation and is perpendicular to the substrate surface, and exhibit a highly ordered array distribution. The addition of hydrogen can effectively improve the growth rate of MWCNTs and increase the aspect ratio. The height and aspect ratio of MWCNTs can be effectively increased with the increase of growth time. Electrochemical investigation indicated that MWCNTs have high specific capacitance (1.96 mF/cm−2) and excellent rate capability (81.6%).

We investigated the growth process of vertically-oriented graphene nanosheets (VGs) on a Si substrate by helicon wave plasma chemical vapor deposition (HWP-CVD). The results show that VGs has good vertical orientation on Si and the growth process does not require the catalyst. Modulation of height, thickness and mesh size of vertical graphene nanosheets can be achieved by changing the growth time. It is found that the height of VGs is linear with time. Extremely high growth rate, approximately 0.26 μm/min, is achieved, in contrast to previous studies. The results of Cyclic voltammetry (CV) measurement indicating that VGs have a very rapid current–voltage response, an excellent electrochemical reversibility and excellent capacitive behavior. The VGs was able to deliver an outstanding specific capacitance value of 345 μF/cm2, and demonstrated an excellent rate capability, which retained 94.41%.