Mastering the Wrinkling of Self-supported Graphene

We present an approach that allows for the preparation of well-defined large arrays of graphene wrinkles with predictable geometry. In general, any topological defects in graphene, such as wrinkles, can effectively modify the intrinsic properties of graphene by varying the electrostatic potential of the layer. We created wrinkled graphene networks on hexagonal arrays of SiO2 nanopillars with different dimensions, varying pillar heights and inter-pillar distances. Chemical vapor deposition (CVD)-grown graphene transferred onto the pillar arrays forms a complex network of two main different types of wrinkle arrangements. The first type is composed of arrays of aligned equidistantly separated parallel wrinkles propagating over large distances, and2 originates from line interfaces in the graphene, such as thin, long wrinkles and graphene grain boundaries. The second type of wrinkle arrangement is formed by non-aligned short wrinkles, which are formed in areas without line interfaces. Apart from the presented hybrid graphene topography with distinct wrinkle geometries induced by the pre-patterned substrate, the graphene layers are suspended and self-supporting, exhibiting a large surface area and negligible doping effects from the substrate. All these properties make this wrinkled graphene candidate a material with enhanced chemical reactivity that is useful in nanoelectronic applications.