van der waals interactions of graphene membranes with a sharp silicon tip

Adhesive interactions of suspended graphene membranes were studied by using non-contact atomic force microscopy (AFM) with a sharp silicon tip. Circular graphene membranes were prepared by transferring large-area monolayer graphene onto a perforated substrate. The non-contact AFM imaging showed a fluctuation of the graphene membrane. The maximum deflection of a 2.7- μm-diameter membrane was about 26.8 nm. The dynamic deflection of the membrane is attributed to the van der Waals interactions between the graphene membrane and the silicon tip of the AFM, and the interaction force was estimated to be about 3.0 nN.