Study on field emission and photoluminescence properties of ZnO/graphene hybrids grown on Si substrates

Zinc oxide/graphene (ZnO/G) hybrids are prepared on n-Si (1 0 0) substrates by electrophoretic deposition and magnetron sputtering technique. The crystal structure, morphology and photoluminescence (PL) properties of the ZnO/G hybrids are analyzed via X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM) and fluorescence–phosphorescence spectrometer, respectively. The results indicate that the crystal quality of ZnO nanostructure deteriorates after depositing graphene buffer layer. Whereas many three dimensional stacking blowballs form in the ZnO/G hybrid, creating a larger surface area than that of ZnO nanostructure. The photoluminescence (PL) spectrum of the ZnO/G hybrid contains multi-peaks, which are consistent with ZnO nanostructure except for two new peaks at 390 and 618 nm. In addition, field emission measurement reveals that Eto and Ethr decrease from 8.01 V μm−1 and 14.90 V μm−1 of the ZnO nanostructure to 2.72 V μm−1 and 7.70 V μm−1 of the ZnO/G hybrid. ZnO/G hybrid is characteristic of having excellent emitting behavior suitable for application in field emission technology.

► Via EDP and magnetron sputtering technique, ZnO/G hybrids were prepared.
► The field emission and PL of the ZnO/G hybrids are characterized.
► Carbon from graphene buffer layer affects the native defect concentrations.
► Carbon plays an important role in the origin of the orange emission at 618 nm.
► ZnO/G hybrid is characteristic of having excellent emitting behavior.