Growing graphene and 2D-materials requires the formation of large domains of single layer thickness, extending over the mesoscale. Diffraction is a very good tool to judge the quality of a material. Surface diffraction with a beam of electrons has, shown a very strong bell-shaped background around the (00) and G(10) graphene pots. This background is very intense and very broad. Textbook diffraction states that the more flawless a material is, the sharper and clearer the diffraction spots, and imperfect materials have low intensity, broader diffraction spots.
By studying the graphene diffraction pattern as a function of the energy of the electrons we find this broad component to be an intrinsic feature to graphene, and when you have it, you have very good graphene. This can be a very good diagnostic of t graphene structural quality. Its origin is related to the spatial confinement of the graphene electrons normal to the surface.
S. Chen, M. Horn von Hoegen, P. A. Thiel and M. C. Tringides. Phys. Rev. B 100, 155307 (2019) "Diffraction paradox: An unusually broad diffraction background marks high quality graphene"