Ultrahigh field emission current density from nitrogen-implanted ZnO nanowires

An ultrahigh field emission current density of 10.3 mA cm(-2) was obtained from nitrogen-implanted ZnO nanowires. The sample was characterized and clearly showed a nitrogen doping signal. Field emission properties of the ZnO nanowires were considerably improved after N-implantation with lower turn-on field and a much higher current density. Removal of an amorphous layer, the presence of nanoscale protuberances, and surface-related defects were found to be responsible for the significantly enhanced field emission. Our work is important for the possible applications of ZnO nanowires in flat panel displays and high brightness electron sources.