Uniformity conditioning of diamond field emitter arrays

The authors present recent advances in the uniformity conditioning of diamond field emitter arrays (DFEAs). Postfabrication conditioning procedures consisting of thermal annealing and high field/current operation have been examined. Nonuniformity due to varying contamination states of the emitters can be mitigated by moderate temperature (∼150–300°C) operation. Operating the emitters at elevated current levels was found to enhance the spatial uniformity in a self-limiting manner. The conditioning mechanism is most likely thermal-assisted field evaporation of the diamond nanotips, however, the nature of the dc tests does not definitively exclude back bombardment as a possible contributor. Pulsed testing is underway to remove this ambiguity, provide conditioning for high-density arrays, and demonstrate the operational current density limits of DFEAs.