Size-dependent torsional deformation of silicon nanowires

摘要

The effect of size on the torsional deformation of [1 1 0]-oriented silicon nanowires is examined via molecular dynamics simulations. The plastic deformation mechanism of silicon nanowires depends on the nanowire diameter. Sub-5.7-nm-diameter silicon nanowires yield by means of a crystal-to-amorphous transition, which nucleates at the outer surface and propagates along the cross-section of the wires. On the other hand, perfect dislocations nucleate at the outer surface of wires whose diameter equals or exceeds 7.7 nm, initiating plastic deformation. These dislocations have a Burgers vector of 1/2 110 and slip along the {1 1 1} planes. These findings may enhance our understanding of plasticity of silicon nanowires. (C) 2017 Elsevier B.V. All rights reserved.