Enhanced Field Emission From Aligned ZnO Nanowires Grown on a Graphene Layer With Hydrothermal Method

Zinc oxide (ZnO) nanowire arrays on silicon substrates with amorphous carbon or graphene as buffer layer for field electron emission application are obtained using hydrothermal method. It is found that graphene could optimize the structure and morphology of ZnO nanowires grown on it. Smaller nanowire diameter and larger length/diameter ratio are obtained for those grown on graphene buffer layer. ZnO nanowires grown on graphene layer has c-axis preferential orientation, while those grown on bare silicon wafer without any buffer layer has no obvious preferred growth orientation. Low turn-on electrical field of 1.59 V/μm and high field enhancement factor of 1625 are obtained from ZnO nanowires grown on graphene layer, which indicates that graphene is not only beneficial to the growth of ZnO nanowires by improving their configuration but can also enhance their field electron emission.