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Key to direct graphene transfer is the control of water intercalation

(Nanowerk News) In new work, reported in ACS Applied Materials & Services ("Controlling Water Intercalation Is Key to a Direct Graphene Transfer"), researchers in Belgium demonstrate that interfacial water can insert between graphene and its growth substrate despite the hydrophobic behavior of graphene.
In their paper, the researchers discuss in detail graphene delamination from platinum (Pt) surfaces using electrochemical methods. They show that water intercalation between graphene and a Pt surface is critical to achieve a successful graphene delamination using an electrochemical method.
They also demonstrate that intercalation effects can occur between graphene and a target wafer, resulting in unwanted graphene delamination effects.
direct graphene transfer
The proposed process. (© ACS)
Exposing a platinum/graphene sample for several days to ambient conditions or submerging it in warm ultrapure water gradually changes the graphene surface morphology and varies the chemical composition of the graphene/Pt interface.
The results are consistent with water intercalation, which progressively develops at the interface. This intercalation process is essential to obtain a successful electrochemical graphene delamination procedure.
Furthermore, the team established a direct graphene transfer process on the basis of interfacial water between graphene and the CVD growth substrate and of avoiding water intercalation between the hydrophobic target wafer and graphene.
Such a direct graphene transfer avoids polymer contamination (no temporary support layer) and etching of the catalyst metal. As a result, recycling of the growth template becomes feasible.
"Since the interaction between graphene and water is comparable to the interaction between MoS2 and water, a transfer procedure based on controlling water intercalation might also work for other 2D materials like MoS2," the authors conclude their report. "As a result, the proposed transfer process might even open the door for the predicted atomic-scale interlocking-toy-brick stacking of different hydrophobic 2D materials."
Michael Berger By – Michael is author of three books by the Royal Society of Chemistry:
Nano-Society: Pushing the Boundaries of Technology,
Nanotechnology: The Future is Tiny, and
Nanoengineering: The Skills and Tools Making Technology Invisible
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