Graphene oxide and reduced graphene oxide coating on 1D NiO nano-forest structure for strong adhesion and efficient field emission

The field emission’s stability of a hybrid materials is influenced by a range of parameters. In this study, we report on a hybrid material composed of 1D nickel oxide nano-forest-like structures (NiOF) with the coating of graphene oxide (GO)/reduced graphene oxide (rGO). The NiOF structures were synthesized directly onto nickel (Ni) foil and subsequently coated with GO/rGO. To evaluate the adhesion strength of the GO and rGO films to the NiOF nanostructures, nano-scratch tests were performed on both the NiOF substrate and the hybrid GO/rGO substrates. Field emission performance exhibits a significant enhancement in the NiOF_GO hybrid compared to the NiOF substrate alone, and this performance was further enhanced in the NiOF_rGO sample. The adhesion energies for the NiOF_GO and NiOF_rGO samples were measured at 2.46 J/m² and 1.2 J/m², respectively. These variations in adhesive energy correlate directly with the stability of field emission in both the bare and hybrid substrates. It was observed that a higher adhesive nature of the coating results in improved field emission stability.