Field emission from laser cut CNT fibers and films

Field emission (FE) measurements are reported from carbon nanotube (CNT) fibers and laser-patterned free standing films fabricated by direct online condensation from a floating catalyst chemical vapor deposition reactor. Fiber and film cathodes showed stable emission in the 1–2 mA current (I) range at maximum cathode temperatures less than 1000 °C; film cathodes show localized heating at the triangular tips and higher maximum temperatures than the fibers. Fowler-Nordheim (FN) analysis indicated a change in the morphology of the emitters with increasing external electrical field (Eext). Fiber cathodeI-Eextdata are interpreted as FN emission from the fiber tip which is eventually limited by space-charge effects. At higherEext, FN emission from the fiber sidewall occurs. The single fiber cathode stopped emitting abruptly when field induced self-heating effects became significant. For CNT films, self-heating effects can destroy a portion of the film, but FE can still occur from other areas.