Highly collimated electron beams from double-gate field emitter arrays with large collimation gate apertures

Electron collimation in field emitter arrays with electron extraction gate and collimation gate electrodes is studied with the goal to develop a high-brightness high current cathode. Using metallic field emitter arrays prepared by the molding method, we fabricated a stacked double-gate device with the two gates differing in diameter by a process utilizing focused-ion beam milling. We measured the field-emission beam characteristics and demonstrated a reduction of the emission angle by a factor of 7.1 +/- 0.8 with minimal emission current decrease under collimating conditions, resulting in a current density increase by a factor of 13.9 +/- 1.0. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3551541]