Figure 3
(a) Large-field micrograph of Van-der-Waals heterostructures of graphene and hBN on 1.5 µm SiO2 on silicon substrate (obtained by stitching and contrast enhancement), (b) comparison of calculated and measured deviation with respect to the bare substrate of minima of graphene-hBN heterostructures on 1.5 µm SiO2 on silicon substrate for NA = 0.35 (see Fig. 2b for the definition of the numbers of the minima), (c) measured and (d) calculated change of the fourth (cf. Fig. 2b) reflectance minimum of graphene-hBN heterostructures on 1.5 µm SiO2 on silicon substrate for different objective lenses (i.e. NAs) and (e) and (f) comparison of measured and calculated changes of the spectral position of reflectance minima of graphene-hBN heterostructures on 625 nm (first minimum) and 1.5 µm SiO2 (fourth minimum) on silicon substrate.
