Fracture of a silicon nanowire at ultra-large elastic strain

Abstract

Understanding the fracture behavior of one-dimensional (1-D) nanomaterials is critical for their functional device applications and maximizing their service life. At the nanoscale, solid materials’ fracture properties could significantly deviate from their bulk counterparts. Our recent study (Zhang et al. in Sci. Adv. 2(8):e1501382, 2016. https://doi.org/10.1126/sciadv.1501382) showed that silicon (Si) nanowires, one of the most important functional 1-D nanomaterials for nanoelectronics and nano-electro-mechanical systems, demonstrated distinctly different mechanical properties than microscale and bulk Si crystals with the elastic strain up to 10% or even more, approaching their theoretical elastic limit. It is therefore intriguing to understand the fracture behavior of a Si nanowire under such deep ultra-strength, as well as their failure mechanisms. In this work, we will experimentally study the fracture behavior of ultrahigh elastic Si nanowires in situ and quantitatively understand their fracture mechanics with the assist of molecular dynamics simulations. The insights obtained in this nanomechanical study may be of help on the development of robust Si nanowire-based mechatronic devices.