Room temperature dislocation plasticity in silicon

We present direct observations of room temperature dislocation plasticity in single crystalline silicon. Previous studies have shown that phase transformation and fracture are the relevant mechanisms of deformation in silicon. In contrast, using in-situ nanoindentation in a transmission electron microscope we find dislocation nucleation and metal-like flow. The results of finite-element modelling suggest that the presence of free surfaces in our unique sample geometry leads to preferential surface nucleation of dislocations and the suppression of phase transformation.