The field emission properties of amorphous hydrogenated carbon (a-C:H) films and nitrogenated a-C:H (a-C:H:N) films subjected to 10 keV Co-60 ion implantation are investigated as a function of ion dose. The average threshold electric field for conditioned nitrogenated and non-nitrogenated unimplanted films is found to be 27 and 29 V/mu m. Implantation of C-60 ions to a dose of 7.5 x 10(13) cm(-2) results in an increase in the threshold field of both the nitrogenated and non-nitrogenated films. However, implantation to a dose of 1.25 x 10(14) cm(-2) results in a reduction in the threshold fields to values close to those found in the unimplanted samples. At larger doses of 2.65 x 10(14) cm(-2), the threshold field for the non-nitrogenated samples remain largely unchanged though there is an increase in the refractive index consistent with an increase in the optical density of the film. In the nitrogenated film, the average threshold field at the highest dose again increases to values comparable to those found for C-60 implantation into virgin single crystal Si. The microstructural changes that take place during implantation and the role of sp(2) rich conductive layers art: discussed.