Scanning focused laser activation of carbon nanotube cathodes for field emission flat panel displays.

We report a scanning focused laser technique for pixel-by-pixel activation of the screen-printed carbon nanotube cathodes for field emission flat panel displays. The turn-on and working field of the cathodes became as low as 1.96 V microm(-1) and 2.70 V microm(-1), respectively, after 57 kW cm(-2) laser irradiation. The current density even reached 4.00 mA cm(-2) at 2.90 V microm(-1), which was 1285 times larger than the untreated one. This dramatic enhancement is due to the fact that the focused laser can remove not only the surface contamination, but can change the geometric structure of the treated pixel as well. More importantly, these laser activated carbon nanotube cathodes show much more uniform field emission performances, as required by flat panel displays.