Adhesion energy of few layer graphene characterized by atomic force microscope

This paper presents a generic approach to characterize and analyze the adhesion energy between graphene and different materials using nanoindentation of an atomic force microscope (AFM), which is extremely essential and critical for variety of graphene based micro- and nano-devices. AFM was used to press a free-standing graphene beam down to a substrate. During the retraction, the adhesion force (named as the secondary pull-off force) was measured to analyze the adhesion energy between the graphene beam and the substrate. This approach is easy for manipulation and it can detect the adhesion energy after the device fabrication. According to our measurement, the graphene/SiO2, graphene/gold, and graphene/graphene adhesion energies per area are approximately 270 mJ/m2, 255 mJ/m2, and 307 mJ/m2, respectively. This result was used to predict the performances and guide the design of graphene M/NEMS devices.