Long term current stability of commutable colc cathodes based on vertically aligned carbon nanotubes

A new way to improve the current stability of an in-plane gated CNT emitters cathode with a closed loop control has been investigated. Ageing has been performed with a variation of external conditions by introducing hydrogen into the vacuum chamber and resulting in a low impact on the stability due to the feedbacked adjustment of the local electric field at the apex of CNTs given by the closed loop control. This structure also shows strong stability over time in normal conditions.