ELECTRON FIELD-EMISSION RESULTING FROM HIGH-DENSITY BREAKDOWN SITES ON AMORPHOUS CARBON-POLYIMIDE COMPOSITE FILMS

Amorphous carbon-polyimide composite films (a-C:P) were prepared by la ser ablation using a 266 nm wavelength fourth harmonic YAG laser. A ro tating target for deposition composed of half a pyrolytic graphite tap e and half a 0.12 mm thick polyimide sheet. A high-density breakdown s ite of similar to 10(6)/cm(2) was obtained while field emission experi ments were pet-formed on the a-C:P films. After breakdown, the turn-on field decreased and the total emission current increased. Permanent b reakdown sites with crater-like structures were formed on a large brea kdown area of 0.3 cm(2) due to a quasi-explosion process. A mean emiss ion site density of 10(5)/cm(2) on some breakdown regions was obtained . The crater structure was found to be a potential candidate for emitt ing electrons with a low turn-on field of 4 V/mu m.