Growth and field emission properties of tubular carbon cones

New forms of tubular carbon cone (TCC) were grown on gold wires by hot-filament chemical vapor deposition (HFCVD). They have a long-cone-shaped appearance with a herringbone hollow interior, surrounded by helical sheets of graphite that are coiled around it. It is considered that TCC formation results because the size of the catalyst particle located in the top of the TCC decreases continuously during growth, due to etching effects in the CVD plasma, reflecting competition between the growth and etching processes in the plasma. In addition, field emission measurements show that TCCs have a very low-threshold field of 0.27 V/μm, and that a stable macroscopic emitting current density of 1 mA/cm2 can be obtained at only 0.5 V/μm. TCCs have good field emission properties, compared to other forms of carbon field emitter, and may be good candidates for use in field emission display devices.