Field emission from vertical Graphene flakes grown on copper particles by CVD method

Field emission of Graphene is limited by the surface morphology because the existing deposition methods lead to Graphene flakes that lay flat on the substrate. To overcome this problem, we grow vertically aligned Graphene flakes on Cu particles using chemical vapor deposition method. The Graphene flakes are oriented at some angles with respect to the substrate, leading to good field emission performance. This can be attributed to the enhanced local electric field at the tips and edges of the vertical Graphene flakes as well as the electrical conductivity enhancement due to the existence of Cu particles. Compared with the flat Graphene layer grown by CVD method, the vertical Graphene flakes show a better field emission performance, with a lower turn-on voltage and a larger current density. The results are of significance to the Graphene based field emission device.