Graphene nanoblisters on nickel

In this work, we exploited the extraordinary flexibility and mechanical strength of graphene coupled with its thermal instability on certain transition metals such as nickel to promote the dissolution of the largest part of a graphene layer into the substrate, while a small portion of it is forced to keep afloat, owing to the presence of an assembly of Ar atoms underneath.
By means of irradiation with low energy Ar+ ions, we have trapped remarkable quantities of Ar, equivalent to 15% of the substrate surface atoms, under epitaxial graphene monolayers on Ni(111). At high temperature, the Ar atoms below graphene assemble into solid clusters: real time HR-XPS shows that while graphene in direct contact with the Ni surface decomposes, the floating graphene regions encase the Ar aggregates forming graphene nanosized blisters (GNBs), evenly distributed on the bare substrate surface and stable in a wide temperature range.

STM images reveal the morphology of the blisters and confirm that GNBs are surrounded by the bare Ni(111) surface.
The known instability of graphene on several transition metals, and probably on their alloys, prefigures the extension of this method to a variety of other substrates. Different GNB shapes and lateral dimensions might be achieved by changing the size of the intercalated rare gas atoms.