Secondary electron emission of graphene-coated copper

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The secondary electron emission of graphene-coated copper has very interesting properties. In this work, we prepared graphene-coated copper foil and measured both the secondary electron emission yield (SEY) and the secondary electron energy spectra. Compared with the copper base, there is a significantly reduction for the SEY. For the copper base without coating, the max value of SEY is beyond 2.1 for the primary electron energy of 300eV. However, the corresponding value for the graphene-coated copper is about 1.5, reduced about 25%. For the secondary electron energy distribution, the elastically backscattered peak becomes higher and peak of the true secondary electrons is shifted from about 1.5eV to 4eV after coating the copper with graphene. The full width at half maximum of the true secondary electrons peak is also increased. Since the position of the peak is related to the surface potential barrier of the material, we believe that the graphene coating could increase the surface potential barrier of the material. This could also be the reason of SEY reduction because a higher potential barrier can reduce the electron emission from the material. A preliminary theoretical model of the surface potential distribution for copper surface with graphene coating was built and used to analyze the secondary electron emission of metal surface with graphene coating. The graphene coating is found to be an effective method to suppress the secondary electron emission.