  Using nanoparticles to impart extrinsic rippling in graphene is a relatively
new method to induce strain and to tailor the properties of graphene. 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 by Langmuir-Blodgett technique on Si
substrate. We show that the transferred graphene follows only roughly the
morphology induced by nanoparticles. The graphene membrane parts bridging the
nanoparticles are suspended and their adhesion to the AFM tip is larger
compared to that of supported graphene parts. These suspended graphene regions
can be deformed with forces of the order of 10 nN. The elastic modulus of
graphene was determined from indentation measurements performed on suspended
membrane regions with diameters in the 100 nm range.
