Field emission beam characteristics of single metal nanotip cathodes with on-chip collimation gate electrode

Field-emission and beam collimation characteristics of single metal nanotip devices with double-gate electrodes are studied. Applying a previously developed method to fabricate all-metal double-gate nanotip arrays with a stacked on-chip extraction G$_{ext}$ and collimation G$_{col}$ gate electrodes with the large G$_{col}$ apertures, the authors produced single double-gate nanotip devices and measured their beam characteristics. Excellent beam collimation capability with minimal reduction of the emission current and the enhancements of the current density up to a factor of ∼7 was observed. The results indicate that these single nanotip devices are highly promising for electron beam applications that require extremely high brilliance and coherence