Real-time observation of epitaxial graphene domain reorientation

Abstract

Graphene films grown by vapor deposition tend to be polycrystalline due to the nucleation and growth of islands with different in-plane orientations. Here, using low-energy electron microscopy, we find that micron-sized graphene islands on Ir(111) rotate to a preferred orientation during thermal annealing. We observe three alignment mechanisms: the simultaneous growth of aligned domains and dissolution of rotated domains, i.e., "ripening"; domain-boundary motion within islands; and continuous lattice-rotation of entire domains. By measuring the relative growth velocity of domains during ripening, we estimate that the driving force for alignment is on the order of 0.1 meV per C atom and increases with rotation angle. A simple model of the orientation-dependent energy associated with the moiré corrugation of the graphene sheet due to local variations in the graphene-substrate interaction reproduces the results. This work suggests new strategies for improving the van der Waals epitaxy of 2D materials.

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Cited by in corpus (5)

• Driving with temperature the synthesis of graphene films on Ge(110)
• On the rotational alignment of graphene domains grown on Ge(110) and Ge(111)
• Lateral heterostructures of hexagonal boron nitride and graphene: BCN alloy formation and microstructuring mechanism
• Abrupt changes in the graphene on Ge(001) system at the onset of surface melting
• Positional and Rotational Molecular Degrees of Freedom in a Metal-Organic Surface Alloy: the Copper-Fullerene System and its Multiple Structural Phases