From a closer inspection of the regions where the NPG film exfoliated in Fig. , we observe that the bare Au surface is no longer smooth. Compared to the NPG film formed from Au oxide prepared at 540 V and 30 s where the NPG structure was randomly torn apart, we find here instead randomly distributed holes within the underlying Au substrate. More specifically, from the SEM images with higher magnification in Fig. , it is apparent that the holes on the Au(111*) facet have a triangular shape, while those on the Au(100*) facet have a square/rectangular shape. The shape of the holes is hereby directly related to the crystallographic orientation of the substrate, substanti-ating our assignment of the different regions to specific crystallographic orientations.