Field-Electron Emission from Single-Walled Carbon Nanotubes Lying on a Surface

Single-walled carbon nanotubes are excellent candidates for electron emitters because of their sharp geometry, mechanical strength and capacity for carrying extremely high current densities. So far, the majority of field-emission experiments have been conducted on structures containing brushes of vertically-aligned nanotubes, or individual freestanding ones mounted on a sharp tip. However, nanotubes lying on a dielectric surface can present advantages due to higher mechanical stability and ability to carry more current. Here, electron emission from individual single-walled nanotubes resting on a silicon dioxide surface is investigated. It is observed that these emitters do not follow the traditional Fowler-Nordheim model. These devices could have a wide range of applications in field-emission displays, electron-beam lithography and microscopy systems, free-electron analog to digital converters, and nanoscale vacuum tubes.