Abstract:This letter presents the application of electrostatic pull-in instability to study the size-dependent effective Young’s Modulus Ẽ ( ~170–70 GPa) of  silicon nanocantilevers (thickness ~1019–40 nm). The presented approach shows substantial advantages over the previous methods used for characterization of nanoelectromechanical systems behaviors. The Ẽ is retrieved from the pull-in voltage of the structure via the electromechanical coupled equation, with a typical error of ≤ 12%, much less than previous work in the field. Measurement results show a strong size-dependence of Ẽ. The approach is simple and reproducible for various dimensions and can be extended to the characterization of nanobeams and nanowires.