Nitrogen Doping of Amorphous Carbon Surfaces

Abstract

The surface properties of amorphous carbon ( $a\ensuremath{-}\mathrm{C}$) are studied using first-principles electronic structure methods. The effect of nitrogen doping near the surface and, in particular, 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 $a\ensuremath{-}\mathrm{C}$ surface at ``on top of the surface'' ${\mathrm{sp}}^{1}$ and ${\mathrm{sp}}^{2}$ sites. Nitrogen doping by low energy ion bombardment is suggested as a doping method to minimize work function of the $a\ensuremath{-}\mathrm{C}$ surfaces.