Research of large current from a composited cold cathode with different spacer gaps

Fabrication and testing process is as follows: firstly, Ag electrode is printed on the silicon substrate with a screen-printing method, 4 hours should be taken for barking at 550 °C. In the second step, cold cathode emitter should be prepared by the combination of carbon nanotubes (CNTs) and ZnO´s slurry at a certain proportion. With the same screen-printing method, we print the composite emitter on the Ag electrode; 3 hours should be taken for barking at 300 °C, the shape of this emitter is a circle with a diameter of 4mm. Finally, we put the cold cathode into a vacuum chamber, and the field-emission performance is measured under pressure of 3x10^-4 Pa with a simply diode structure. By changing different cathode-anode gaps, we get several sets of data.