  The electronic properties of graphene can be significantly influenced by
mechanical strain. One practical approach to induce strain in graphene is to
transfer this atomically thin membrane onto pre-patterned substrates with
specific corrugation. The possibility to use nanoparticles to impart extrinsic
rippling to graphene has not been fully explored yet. Here we study the
structure and elastic properties of graphene grown by chemical vapour
deposition and transferred onto a continuous layer of SiO2 nanoparticles with
diameters of around 25 nm, prepared on Si substrate by Langmuir-Blodgett
technique. We show that the corrugation of the transferred graphene and thus
the membrane strain can be modified by annealing at moderate temperatures. The
membrane parts bridging the nanoparticles are suspended and can be reversibly
lifted by the attractive forces between an atomic force microscope tip and
graphene. This allows the dynamic control of the local morphology of graphene
nanomembranes.
