Exploration and mechanism analysis: The maximum ultraviolet luminescence limits of ZnO/few-layer graphene composite films

In this paper, ZnO films were deposited on the surface of few-layer graphene films by RF magnetron sputtering and its photoluminescence performance was studied. Large-area few-layer graphene films were prepared on a Cu substrate by CVD. To improve the crystalline quality and c-axis preferred growth orientation of ZnO films, we systematically optimized the process parameters (RF power, working pressure, substrate temperature, the flow ratio of Ar and O-2) of growing ZnO on graphene films. After optimizing the growth process of ZnO on the graphene surface, the enhancement effect of graphene film on the PL properties of the ZnO layer was studied. We explored the influence of ZnO thickness on the PL performance. On the one hand, the optimal process parameters of growing ZnO on the surface of graphene films by magnetron sputtering were investigated; on the other hand, the sputtering time was optimized to make the composite films have the strongest UV emission performance with the lowest visible range.