On the uniformity of field emission in screen printed CNT-cathodes: The effects of the cathode roughness

The relationships between the cathode roughness such as protuberances and the trace of the electron beams were given by numerical result for the first time. Simulation results tell that a micron or sub-micron protuberances on the cathode will affect the electron trace remarkably and the divergence of the electron beam is sensitive to the size of protuberance. Further more, a quantitative result of effecting region of the protuberance was given. It's also revealed that the cathode roughness near the edge will give rise to the opportunity of the charge up of the insulator layer and miss addressing because of a raised divergent angle. And this conclusion was confirmed in luminescent pixels by the trails of electron beams, whose divergent angle was greatly increased by the edge field. According to the simulation result, a special treatment was adopted to enhance the uniformity of field emission, and a uniform luminescent pixels array was achieved.