Demonstration of 3-D-Printed Field-Emission Cathodes

We report the first operation of field-emission cathodes produced from electrically conductive polymers using 3-D printing. These cathodes consisted of a single high-aspect-ratio emitter printed using a commercially available fused filament fabrication (FFF) printer. Emitters were printed from one of three commercially available polylactic acid (PLA) composite filaments. Each material produced appreciable field-emission currents, and an emitter with 0.4 mm diameter and 15 mm length sustained a dc current of 2.25 mA (similar to 1.8 A/cm(2)) for approximately 1 h before noticeable current degradation occurred. These initial experiments suggest that 3-D printing can provide a low-cost fabrication technique for future field-emission studies with novel cathode geometries.