Effects of Surface Stress on Nanocantilevers

Surface and interface effects play significant roles in mechanical properties of nanostructures. Traditional continuum mechanics does not account for surface and interface effects on the elastic behavior of nanostructures. This work presents a general Lagrangian mechanics framework to describe the surface elastic properties. This model includes the surface effects on overall elastic behavior of a nanocantilever. It is demonstrated that the overall elastic behavior of the nanostructures is scale-dependent. Silicon nanocantilever have been fabricated with dimensions from 200 to 8 μm length, 25 to 4 μm width and 1 μm, 340 nm, and 93 nm thicknesses. The resonance behavior is studied and is compared with resonance frequency measurement in order to see at which scale other surface effects become significant. [DOI: 10.1380/ejssnt.2009.161]