We demonstrate a technique to strain two-dimensional hexagonal boron nitride (hBN) and graphene by depositing stressed thin films to encapsulate exfoliated flakes. We choose optically transparent stressors to be able to analyze strain in 2D flakes through Raman spectroscopy. Combining thickness-dependent analyses of Raman peak shifts with atomistic simulations of hBN and graphene, we can explore layer-by-layer strain transfer in these materials. hBN and graphene show strain transfer into the top four and two layers of multilayer flakes, respectively. hBN has been widely used as a protective capping layer for other 2D materials, while graphene has been used as a top gate layer in various applications. Findings of this work suggest that straining 2D heterostructures with evaporated stressed thin films through the hBN capping layer or graphene top contact is possible since strain is not limited to a single layer.
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Large‐Area Single‐Crystal Graphene via Self‐Organization at the Macroscale
In 1665 Christiaan Huygens first noticed how two pendulums, regardless of their initial state, would synchronize. It is now known that the universe is full of complex self‐organizing systems, from neural networks to correlated materials. Here, graphene flakes, nucleated over a polycrystalline graphene film, synchronize during growth so as to ultimately yield a common crystal orientation at the macroscale. Strain and diffusion gradients are argued as the probable causes for the long‐range cross‐talk between flakes and the formation of a single‐grain graphene layer. The work demonstrates that graphene synthesis can be advanced to control the nucleated crystal shape, registry, and relative alignment between graphene crystals for large area, that is, a single‐crystal bilayer, and (AB‐stacked) few‐layer graphene can been grown at the wafer scale.
more » « less- NSF-PAR ID:
- 10455045
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials
- Volume:
- 32
- Issue:
- 45
- ISSN:
- 0935-9648
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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