Vertical epitaxial Co5Ge7 nanowires and nanobelts arrays on a thin graphitic layer for flexible FED

We have successfully synthesized vertically aligned single-crystalline Co₅Ge₇ NWs on a curved thin graphite layer as well as on a very thin graphite layer. Vertical Co₅Ge₇ nanobelts are also synthesized on a graphite substrate. The vertical Co₅Ge₇ nanobelt arrays or Co₅Ge₇ NW arrays have been selectively grown on a graphite substrate depending on the experimental conditions. As grown Co₅Ge₇ NW arrays satisfy most requirements for the ideal emitters of FEDs, such as sharp tips, superb electrical conductivity, thermal and chemical stability, and vertical alignment to the substrate. The vertical Co₅Ge₇ NW arrays showed very efficient FE properties comparable to those of CNTs because of their optimum morphology. The NW emitter arrays on the curved graphite layer could be used for future flexible FEDs. Since the crystal structure of thin HOPG is close to that of graphene layers, our results could be extended to the epitaxial growth of Co₅Ge₇ NWs and nanobelts on graphene.