Extended Data Fig. 4: Surface roughness of UFG and rough graphene.
From: Uniform thin ice on ultraflat graphene for high-resolution cryo-EM
a-c, AFM images of rough suspended graphene membranes, where dense wrinkles were observed. The dark holes in (b) indicated the broken graphene regions. Scale bars, 3 μm. d-f, AFM images showing the ultraflat suspended graphene membranes with no wrinkles and superior coverage rate. Scale bars, 3 μm. g, Distributions of average surface roughness (Ra) of suspended UFG membranes (olive) and rough graphene membranes (red). Insets: typical 3D AFM images of suspended UFG (left) and rough graphene (right), respectively. The Ra of ultraflat suspended graphene is ~0.7 nm, apparently smaller than that of rough suspended graphene (~2 nm). h, Distribution of maximum height difference (ΔH) along the diameter of suspended UFG (olive) and rough graphene (red). Insets: typical height profiles of suspended UFG and rough graphene, respectively. Most ΔH of UFG distributed around 2 nm, while ΔH of rough graphene exhibited an uneven distribution (10 ± 6 nm). Source data are provided as a Source Data file.
