Atomistic study of the bending properties of silicon nanowires

Abstract

Molecular dynamics simulations are conducted to investigate the mechanical properties and deformation mechanism of silicon nanowires (SiNWs) under pure bending, with a focus on the effects of nanowire diameter, orientation, and cross-sectional shape. The results show that the nanowire diameter and cross-sectional shape do not influence the yield mechanism but the orientation does. In contrast to [1 0 0] and [1 1 0] SiNWs whose yield mechanism is dislocation nucleation, [1 1 1] SiNWs yield by a direct crystal-to-amorphous transition. Moreover, the activated slip plane for [1 0 0] and [1 1 0] SiNWs is different, i.e., {1 1 0} and {1 1 1} plane for [1 0 0] and [1 1 0] SiNWs, respectively. The Young’s modulus of [1 0 0] and [1 1 1] SiNWs is dependent on the nanowire diameter and cross-sectional shape, whereas that of [1 1 0] SiNWs is insensitive to these factors. Furthermore, only the nanowire orientation and cross-sectional shape influence the critical bending strain of [1 0 0] and [1 1 1] SiNWs. The results presented in this work may provide valuable information for the design of nano-devices based on SiNWs.