Structure and photoluminescence properties of graphene nanoflakes grown on zinc oxide films by hot filament chemical vapor deposition

Graphene nanoflakes (GNFs) were grown on silicon substrates pre-coated with different thicknesses of zinc oxide (ZnO) films by hot filament chemical vapor deposition in the methane environment. The structural, compositional and photoluminescence (PL) properties of the synthesized GNFs were systematically and extensively studied using a broad range of advanced characterization instruments including field emission scanning electron microscope, high-resolution transmission electron microscope, Raman spectroscopy, and X-ray photoelectron spectroscopy, etc. It is shown that the GNFs can be synthesized on ZnO films and that the thickness of GNFs reduces with the increased thickness of ZnO films. It is also shown that the GNFs can generate a series of strong green PL bands, but the green PL bands shift towards long wavelengths with the increased thickness of ZnO films. The change in the structural and PL properties of GNFs has been analyzed in terms of the features of graphene nanoribbons and the interfacial interaction of GLFs with ZnO films. These outcomes can contribute to the control of growth and structure of graphene-based materials and the fabrication of the optoelectronic devices relevant to graphene-based materials.