Microstructures, surface states and field emission mechanism of graphene–tin/tin oxide hybrids

The effects of microstructures and surface states on the field emission, which are important to a good understanding of the field emission mechanism, are unclear. In this paper, the microstructures and surface states of graphene–Sn/SnO2 hybrids were analyzed, and the field emission mechanism was explored. Raman spectra and images revealed that SnO2/Sn droplets are strongly bound on graphene surface, and there exist oxygen vacancies at the surface of graphene–Sn/SnO2 hybrids. Among X-ray photoelectron spectroscopy spectra, the peak of O 1s shifts 1.6 eV toward higher binding energies in the 5 min sample with the best field emission properties, which indicates that the field emission improvement in graphene–Sn/SnO2 hybrids arises from the band-bending effect and a lower work function.

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► The microstructures and surface states of graphene–Sn/SnO2 hybrids were analyzed.
► The field emission mechanism was explored based on experimental results.
► The electron emission arises from the band-bending effect and a lower work function.