Engineers at the University of Ulster have created ultra thin, stable diamond nanorods with a diameter as thin as few nm and smaller than all the currently reported diamond 1D nanostructures.
They exhibit a low-threshold, high current-density with field emission performance better than that of all other conventional (Mo and Si tips, etc.) and popular nanostructural (ZnO nanostructure and nanodiamond, etc.) field emitters except for oriented CNTs. Such diamond nanorods are encapsulated in a few graphene layers, which serve as a shield for keeping them stable. The ultra thin DNR is encapsulated in tapered carbon nanotubes (CNTs) in a specific orientation. DNRs are self-assembled into isolated electron-emitting spherules along with diamond nanoclusters and multilayer graphene nanowires. The forming mechanism of DNRs is suggested based on a heterogeneous self-catalytic vapor solid process.
Fabrication

The ultra thin nanords were fabricated in a microwave plasma assisted chemical vapor deposition reactor using a mixture gas of nitrogen and methane gases. Together with some diamond nanocluster, graphene nanowires and carbon nanotubes, diamond nanorods are self-assembled into a spherical electron-emitting structure. This integrated self assembled nanostructure has excellent field electron emission performance, better than that of all other conventional (Mo and Si tips, etc.) and popular nanostructural feld emitters. This novel DNR-based integrated nanostructure has a potential for use as low-power cold cathodes as well as for medical technological applications.