Investigate the interface structure and growth mechanism of high quality ZnO films grown on multilayer graphene layers

The mechanically stable ZnO films with excellent optical properties were directly grown on the graphene layers without any additional treatments by using pulsed laser deposited (PLD). XRD, Raman spectrum and temperature-dependent photoluminescence (TDPL) are employed to study the structure and optical properties of ZnO films grown on the graphene layers. By adopting a plane wave ultrasoft pseudopotential method based on density functional theory, the adsorption binding energy of ZnO molecules deposited on graphene surface is calculated. It is suggested that formation of C-Zn bond rather than the C-O bond during initial stages of adsorption. What are more; the binding energies and interfacial adsorption energy were calculated. It can be concluded that the interface structure model is tend to be graphene-Zn-O-Zn-O in ZnO thin films grown on graphene. The ZnO-graphene nano-film is the promising candidate for potential application in flexible optoelectronic devices.