Extended Data Fig. 3: Raman and AFM characterization of conducting filaments in GO membranes.
From: Electrically controlled water permeation through graphene oxide membranes
a, Topographical SEM image of a GO membrane after the formation of conducting filaments. b–d, Raman intensity ratio (ID/IG) mapping of D and G bands for a pristine GO membrane (b) and a GO membrane after conducting filaments have formed (c, d). c, Raman imaging from the membrane surface close to the positive electrode (about 200 nm away). d, Raman imaging from the membrane surface close to the negative electrode (about 100 nm away). e, f, The Raman spectra from the dark blue and green regions in c, respectively. g–j, Topography and the corresponding TUNA current image of pristine GO (g and h, respectively) and conducting GO (i and j) membranes (filament formed at 100% RH) exfoliated on a gold-thin-film-coated Si substrate. The conducting filaments are marked by red circles. Scale bars, 1 μm. k, Out-of-plane I–V characteristics of a conducting GO membrane with a diameter of about 7 mm before (parent membrane) and after dividing into four equal pieces. Inset, schematic of the structure of conducting carbon filaments in the GO membrane.
