Fig. 4: Controlling the twist angle by adjusting the macroscopic stacking angle.
From: Stacking transfer of wafer-scale graphene-based van der Waals superlattices
a Schematic of controlling the macroscopic stacking angle (α) of double-layer graphene by rotating the orientations of graphene wafer flats. b Photo of the as-transferred double-layer graphene films with macroscopic stacking angle α1 of ~20°, immersing the film in the aqueous solution and adjusting one of the wafer-flat of graphene films parallel to the ruler. c, Adjusting the macroscopic stacking angle α2 at ~0° (i.e. ~ 20° to another graphene), inset is the zoom-in image of the yellow dashed box. d Exhausting the solution, descending the floating PMMA/graphene to finally achieve an initial alignment between the graphene layers. e Graphene films after spinning-assisted transfer process, and inset is the triple-layer graphene films after removing PMMA. f–i, SAED patterns of the triple-layer graphene collected at random locations. The twist angles measured by a dashed line and dashed circle in f are consistent with the macroscopic stacking angles. Insets in g are the relative intensities of the first-order and second-order SEAD spots, the purple and cyan lines represent the intensity profiles of the double-layer graphene with the twist angle of ~0° and the other monolayer graphene, respectively.
