Field emission enhancement of amorphous carbon films by nitrogen-implantation

Effect of nitrogen-implantation on electron field emission properties of amorphous carbon films has been examined. Raman and X-ray photoelectron spectroscopy measurements reveal different types of C–N bonds formed upon nitrogen-implantation. The threshold field is lowered from 14 to 4 V/μm with increasing the dose of implantation from 0 to 5 × 1017 cm-2 and the corresponding effective work function is estimated to be in the range of 0.01–0.1 eV. From the perspective of tetrahedron bond formation, a mechanism for the nitrogen-lowered work function is proposed, suggesting that both the nitrogen nonbonding (lone pair) and the lone-pair-induced carbon antiboding (dipole) states are responsible for lowering the work function and hence the threshold field. [Copyright &y& Elsevier]