Aligned carbon nanotubes with open ends have been fabricated on silicon wafer in one step using a microwave plasma enhanced chemical vapor deposition system with a mixture of methane and hydrogen as precursors. High concentration hydrogen plasma and high negative bias voltage to the substrate induce anisotropic etching of carbon nanotubes and can effectively reduce the randomly oriented carbon nanotubes. The mechanism of aligned carbon nanotubes with open ends is proposed in this letter.

Deep anisotropic LiNbO3 etching with SF6/Ar inductively coupled plasmas J. Vac. Sci. Technol. B 30, 011208 (2012); 10.1116/1.3674282 40-50MHz lithium niobate (LiNbO3) transducers for pulsed Doppler measurements in mouse embryos