Figure 1. Experimental setup.

(a) Device schematic. Inset: SEM image of a representative free-standing graphene membrane (scale bar, 8 μm). (b) Cross-sections of a graphene membrane at various applied voltages. Height data obtained from interferometric profilometry corresponding to these cross-sections are shown in the inset. Also shown is a three-dimensional view of the data at V_g=400 V. (c) AFM measurements of graphene membrane showing nanometre-scale static wrinkles (left, scale bar, 100 nm). A cross section of the AFM data are shown in the bottom panel. Wrinkling is also evident on the high-angle tilted SEM image (right, scale bar, 1 μm).