Nitrogen-doped multilayered nanographene derived from Ni₃C with efficient electron field emission

Stability and durability are crucial to graphene-based field emitting materials. Although well-aligned N-doped graphene has a large aspect ratio and good electrical conductivity, it suffers from weak adhesion to the substrate, electric field shielding, and Joule heating effect and possible damage and collapse may result in dissatisfied field emission properties. Herein, field emitters based on N-doped multilayered nanographene derived from Ni₃C films are demonstrated to have strong adhesion to the substrate and a uniform large-aspect-ratio morphology. Field-emission (FE) measurements, from the channel edges of 250 microns in depth and 1 micron in width covered with N-doped multilayer nanographene, were performed on N-doped multilayered nanographene on Ni/Si-MCPs (N-doped MLG-MCPs), revealing a small turn-on field of 0.5 V μm^-1, a low threshold field of 1.1 V μm^-1, and a large enhancement factor β of 9012 at a distance of 100 μm. In addition, the current density is 2.85 mA cm^-2 and 96.2% retention is observed after operation for 6 h. The performance and stability of N-doped MLG-MCPs are better than those reported previously from doped graphene nanostructures and comparable to those of carbon nanotubes and carbon-based nanocomposites. The materials with a well-aligned nanographene skeleton have great potential as next-generation FE electron sources.