Nitrogen doping of amorphous carbon surfaces

The surface properties of amorphous carbon (a-C) an studied using first-principles electronic structure methods. The effect of nitrogen doping near the surface and, in paritcular, the effect of nitrogen on the work function is studied by doing a series of nitrogen substitutions near the surface. It is found that the work function is reduced by nitrogen doping of the a-C surface at "on top of the surface" sp(1) and sp(2) sites. Nitrogen doping by low energy ion bombardment is suggested as a doping method to minimize work function of the a-C surfaces.