Field emission from gated diamond arrays

Abstract

Diamond field emitter arrays have been developed for use as cold electron sources in flat panel displays and high-power tubes. Diamond was selectively deposited on patterned silicon wafers, and the common problems of field emission from the gate and the walls have been solved by innovative modifications in the processes involved. This resulted in cathodes where the gate area was completely free of diamond. The leakage currents were less than 8% of the total current. The diamond cathodes were tested in two different diode configurations in a UHV system for voltages ranging from 0–20 V. Field emission has been achieved at ultra-low onset voltages of less than 0.25 V and very high currents were obtained. For a voltage of 3 V applied to the gate, for example, corresponding to an electric field of 1.5 V/μm, emission currents of up to 1 mA have been observed and tested for several days without deterioration. At 7 V, a current of 3.5 mA was achieved in this configuration. The onset of field emission for measurements to a flat anode was 0.5 V/μm, and 3.5 mA were reached at 0.8 V/μm.