Effect of Organic SAMs on the Evolution of Strength of Silicon Nanostructures

摘要

The ability to accurately predict the strength of nanoscale, single crystal structures is of interest in micro- and nanoelectromechanical systems (MEMS and NEMS) design. Because of the small length scales involved failure does not always follow the same trends as at larger sizes. Due to low defect density and high surface to volume ratio, failure is primarily dependent on surface features. Previous work has shown that oxidation of the surface of silicon nanostructures correlates to decreased strength and that methyl surface monolayers can be used to slow oxidation and maintain initial strength. We extend these results to use longer chain self-assembled monolayers (SAMs) prepared in a variety of ways. Although only initial results are included here, aging will be carried out over a much longer time period than in previous studies. Fracture tests were performed using an atomic force microscope (AFM) following a method previously demonstrated by Alan et al.