Characterization of three-dimensional nano-carbon field emission emitters

A unique three-dimensional nano-carbon electron emitter film with high emission current density at low electric field has been developed on stainless steel substrate by a direct current plasma chemical vapor deposition system. Scanning electron microscopy image taken from this film indicates that the film contains cone-like emitters whose array density is about 3×10⁶/cm². The center of each emitter is a carbon nanoneedle, and many carbon nano-walls are grown from the needle. Transmission electron microscopy observation reveals that the needles are hollow cone shape with bamboo-joint like structures on the side surface. Carbon nano-wall growth just starts from the bamboo joints. Raman spectroscopy was used to evaluate its graphitization degree and crystallinity. The I-V characteristic exhibits an emission current density of 143mA/cm² at 2.2V/μm, and the field emission current is durable, making it possibly suitable for developing field emission devices.