It was recalled that covalent materials fracture in a brittle manner when the deformation exceeded a few per cent. It was predicted that a macroscopically brittle material like silicon could show nanoscale plasticity. The exceptional plasticity observed in silicon nanocontacts ('nanobridges') at room temperature was studied here using a special experimental set-up combining a transmission electron microscope and a micro-electromechanical system. When accounting for surface diffusion, success was had in elongating the nano-contact into a wire-like structure, with a fivefold increase in volume, up to more than twenty times the original length. Such a large plasticity was caused by the stress-assisted diffusion and the sliding of the intergranular, amorphous-like material among the nanocrystals.

Exceptional Plasticity of Silicon Nanobridges. T.Ishida, F.Cleri, K.Kakushima, M.Mita, T.Sato, M.Miyata, N.Itamura, J.Endo, H.Toshiyoshi, N.Sasaki, D.Collard, H.Fujita: Nanotechnology, 2011, 22[35], 355704