Mechanical Properties of Silicon Nanowires

In this paper that was published a few months ago, we reported the size effects on the elastic modulus and fracture strength of silicon nanowires. In addition, we observed that the silicon nanowires are linear elastic until fracture with a very large fracture strain up to 12%.

Y. Zhu, F. Xu, Q. Qin, W. Y. Fung, and W. Lu, Nano Letters 9, 3934-3939, 2009

Abstract:

The Young’s modulus and fracture strength of silicon nanowires with diameters between 15 and 60 nm and lengths between 1.5 and 4.3 μm were measured. The nanowires, grown by the vapor-liquid-solid process, were subjected to tensile tests in situ inside a scanning electron microscope. The Young’s modulus decreased while the fracture strength increased up to 12.2 GPa, as the nanowire diameter decreased. The fracture strength also increased with the decrease of the side surface area; the increase rate for the chemically synthesized silicon nanowires was found to be much higher than that for the microfabricated silicon thin films. Repeated loading and unloading during tensile tests demonstrated that the nanowires are linear elastic until fracture without appreciable plasticity.