This letter describes the fabrication and operation of diamond grit ga
ted cathodes. The structure is similar to Spindt-type cathode, but the
field emission cone is replaced with a more planar diamond grit layer
50 to 200 nm thick. Although the minimum lithographic dimension of th
ese cathodes is from 1 to 5 mu m, these devices have exceptionally low
turn-on voltages, 5 to 7 V. Cathode current noise is less than 2.5% r
ms with a maximum absolute current variation of 6.7% over a 6 h period
. These de,ices can operate in pressures of nitrogen above 133 Pa (1 T
orr). Although operation in 6.6 x 10(-2) Pa (5 x 10(-4) Torr) with mor
e reactive gasses, O-2 or H2S, degrades performance, the cathodes reco
ver when the pressure is reduced to less than or equal to 1.3 x 10(-4)
Pa (1 x 10(-6) Torr). Gate current varies from 0.2 to 100 times the e
mitted current and depends on the technique used to deposit the diamon
d grit. High current densities (>10 A cm(-2)) low gate voltages (<50 V
), low emission noise, excellent longevity, temporal uniformity, and e
ase of fabrication make these devices potential cathodes for flat pane
l displays. However, excessive gate current and unsatisfactory process
ing reproducibility at present limit their general application.