Field emission properties of screen-printed activated carbons

The electron emission property of various screen-printed activated carbons was studied. Each activated carbon was characterized with a thick film, which was made of photosensitive paste. The activated carbon made of coal showed the highest emission current density (J) of ∼350 (μA/cm2) and with the lowest threshold electric field (Eth) ∼ 4.2 (V/μm). These results were explained by graphitization factor and sp2/sp3 ratio. The data clearly show that the carbon content in the paste is one of the main factors affecting the morphology of the film surface and field emission properties. As the carbon increases, J increases and Eth decreases.