Fig. 9.

(a) Left column: SEM (5 kV) and CuL³VV image of the G-Cu foil with empty and suspended holes. The bright diagonal line visible in both images indicates a grain boundary of the Cu foil, where the foil is bent. Three spectra locations 1, 2 and 3 are indicated: as grown graphene on the Cu substrate (1), suspended membrane (2) and suspended membrane (3). (b) Center column: Sketch of the sample after Au evaporation on the membrane backside together with the local geometry of position 1, 2 and 3 in the SPEM. (c) Right column: C 1s and Au 4f spectra acquired from locations 1, 2 and 3 after Au deposition on the sample backside and the corresponding peak intensities scaled to the ones belonging to position 2. Due to the different sample alignment and the grazing geometry of the secondary electron detector used SEM the Cu support appears slightly darker than the G-membranes compared to the SEM images presented in Fig. 7.