Graphene grown by CVD on Cu foils has generated interest due to low cost and the prospect of large-area monolayer coverage. The initial nucleation and growth dynamics of graphene play a critical role in determining the final film quality. In this work, we investigate the effects of the electrochemical synthesis onto graphene quality, showing the influence of the Cu-Ru interdiffusion. The growth of good quality graphene layers is also discussed in terms of the role played by grain boundaries and diffusion at the grain boundaries. This comparison shows that the graphene having the best quality is produced using a ruthenium sandwich covering a copper core. This setting avoids contaminations from evaporation and recondensation of copper during thermal cycling due to the CVD process.
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