Synthesis of carbon nanocoils by microwave CVD

The carbon nanocoil is an interesting kind of nanomaterial, which is expected to have various novel applications in microelectronics, microelectromechanical systems (MEMS) and bioMEMS due to its nanosize coil morphology. Carbon nanocolls were synthesized by catalytic pyrolysis of acetylene over 2.2-3.0 mum Ni particles at 600degreesC in a microwave chemical vapour deposition (CVD) system. Microwave CVD derived nanocoils are rather uniform with an average coil diameter of 110-170 nm, fibre diameter of 80-120 nm and pitch of around 130-200 nm. The effects of reaction temperature, the size of Ni catalyst and the flow rate of acetylene were examined. Additionally, the growth mechanism of carbon nanocolls was studied. It was found that two individual carbon nanocoils extrude from the same Ni particle in the same direction as straight fibres at the beginning and then bend to grow into nanocolls in opposite directions.