Emission limiting in silicon field emitters

The success of a field emitter array (FEA) as a high frequency or high brightness source is critically dependent on the FEA´s maximum total current and current density. To date, damage and shorts typically limit the maximum current obtained from high current density FEAs (those not containing large resistances in series with each tip). Because it is not clear what mechanism or what per-tip current initiates the damage, it is difficult to predict maximum FEA performance or engineer optimal FEA structures and circuits. Joule and Nottingham heating have been suggested as damage-causing mechanisms. We have measured the total potential drop (and thus energy loss) in Si FEAs by measuring the energy distribution of the beam.