Demonstration of low voltage field emission

The authors describe field emission from a thin-film field emitter array. The process used to fabricate the field emitters is based on the mold technique described by H.F. Gray and R.F. Greene (US patent 4,307,507). Each emitter chip consists of a 10×10 square array of field emitter tips and associated lead bonding pads. There is a 10-μm spacing between emitter tips. The bare chips were packaged by mounting to an alumina substrate, four to eight chips per substrate. The chips were tested in a demountable vacuum system equipped with a movable anode. The testing apparatus makes it possible to accurately measure currents as low as 100 nA at low duty. Fowler-Nordhein-like current-voltage characteristics were measured for most of the chips tested, indicating field emission. Substantial emission currents were observed at less than 20 V. The emitted current was collected almost entirely at the anode: the measured gate current was 1 to 5% of the emitted current