Using an atomic force microscope, we measured effective spring constants of stacks of graphene
sheets less than 5 suspended over photolithographically defined trenches in silicon dioxide.
Measurements were made on layered graphene sheets of thicknesses between 2 and 8 nm, with
measured spring constants scaling as expected with the dimensions of the suspended section,
ranging from 1 to 5 N/m. When our data are fitted to a model for doubly clamped beams under
tension, we extract a Young’s modulus of 0.5 TPa, compared to 1 TPa for bulk graphite along the
basal plane, and tensions on the order of 10
−7
N.© 2007 American Vacuum
Society.DOI: 10.1116/1.2789446