Figure 1

AFM image of graphene. (a) Tapping-mode height image of the graphene sample. A, B, C, and D are labeled for one-, two-, four-, and eight-layer graphene, respectively, while S is labeled for the SiO₂ surface. (b) The profile of the marked line in (a). (c) The measured height (h) as a function the assigned number of graphene layers (n) and the linear fitting result (red line), giving h = 0.37n + 0.15.