Oriented carbon microfibers grown by catalytic decomposition of acetylene and their field emission properties

Carbon fibers with a diameter approximately 1-2 μm have been synthesized by thermal chemical vapor deposition with a mixture of nitrogen and acetylene on nickel-coated silicon substrates in a furnace. The growth temperature was 1000°C. Scanning electron microscopy micrographs showed that grass-like oriented carbon microfibers were produced with a relatively high density of 107/cm2. Nodular carbon structures could be obviously observed along the micro-fibers. This may suggest that those adjacent carbon spherulites probably grew simultaneously upwards to construct the oriented microfibers. The early growth of oriented carbon microfibers was possibly confined by the porous structures of nickel catalyst, which were formed while heat treatment. A threshold electric field as low as 2 V/μm and an emission site density of 104/cm2could be achieved from the oriented carbon microfibers.