Carbon nanostructures: Growth, electron emission, interactions with hydrogen

We introduce the concept of the field enhancement distribution function f(β) for a useful characterization of the field emission properties of thin film emitter and show how this distribution function can be measured by scanning anode field emission microscopy. Using f(β) measured on a thin film of randomly oriented multiwalled carbon nanotubes we show that even these kinds of low cost emitters can show a field emission performance comparable to micro-tip arrays. However the large spread in field enhancement values between the individual emitter prevent this performance to be fully exploited. This because the field-range in which such thin film emitters can be operated is limited due to emitter disruption and triggering of vacuum arcs. Further we briefly discuss the possibilities of using carbon nanostructures for hydrogen storage applications.