Enhanced field electron emission of flower-like zinc oxide on zinc oxide nanorods grown on carbon nanotubes

Abstract

For the first time, zinc oxide (ZnO) nanoflowers on ZnO nanorods were produced on carbon nanotubes (CNTs) synthesised from waste cooking palm oil precursor. First, CNTs were grown using a thermal chemical vapour deposition method. Next, ZnO nanostructures were deposited using the sonicated sol–gel immersion method and the prepared samples were characterised using electron microscopy, micro-Raman spectroscopy and X-ray diffraction. The field electron emission properties of the samples indicated that the ZnO nanoflowers grown on the CNTs had better emission performances than the pristine aligned ZnO nanorods. The resulting CNTs/ZnO nanocomposite had reasonable turn-on and threshold fields of 4.6 and 6.7V/µm, which corresponded with the electric fields required to create current densities of 1.0µA/cm2 and 0.1mA/cm 2, respectively. This study shows the important roles of CNTs in ZnO nanoflowers growth and the abilities of CNTs to enhance ZnO emission properties.