Image: graphene coated copper

Scanning electron microscopy (SEM) is an essential tool for studying graphene. It is particularly useful for graphene that has been grown on copper, as it gives a direct visualisation of the copper surface. The image below is an SEM image from a graphene coated surface. SEM images are normally presented as greyscale, but this one has been false coloured. The surface shows wavy lines of steps in the surface, just like terraced rice fields. The steps are caused by the interaction of graphene with the copper, and tell us that graphene is likely present in this area; without this, it would be challenging to infer whether graphene was there or not.

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A scanning electron microscopy (SEM) image of a graphene coated copper surface. The graphene causes the copper to arrange into a stepped structure.