Image Credits: Promotive/shutterstock.com
Buckytubes are the most popular field emitters of any material. This is obvious due to their high electrical conductivity and the matchless sharpness of their tip (as the tip becomes sharper, the electric field will become more concentrated, resulting in field emission; this is the reason why lightning rods are sharp).
Furthermore, the sharpness of the tip implies that they emit at particularly low voltage, a vital aspect for constructing electrical devices that make use of this feature. Buckytubes can conduct an astonishingly high current density, probably as high as 1013 A/cm2. Moreover, the current is highly stable [B.Q. Wei, et al. Appl. Phys. Lett. 79 1172 (2001)].
Carbon Nanotubes in Field Emission Flat Panel Displays
A direct application of this behavior that has gained significant interest is in field-emission flat-panel displays. Just like a conventional cathode ray tube display, there is a separate electron gun (or many) for each pixel in the display in the place of a single electron gun in this case. With the high current density, steady, long-lived behavior, and low turn-on and operating voltage, Buckytubes are attractive field emitters to enable this application.
Other Field Emission Display Applications of Carbon Nanotubes
Other applications exploiting the field-emission properties of Buckytubes are lightning arrestors, general cold-cathode lighting sources, and electron microscope sources.