Very large current density from carbon nanotube field emitters

Field emitters made from carbon nanotubes exhibit excellent macroscopic emission properties; they can operate at a very large current density, as high as 4 A/cm/sup 2/. At electric fields as low as 4-7 V//spl mu/m, they emit technologically useful current densities of 10 mA/cm/sup 2/. The emission originates from nanotube ends with a characteristic structured ring pattern.