Near-theoretical fracture strengths in native and oxidized silicon nanowires

In this letter, fracture strengths sigma(f) of native and oxidized silicon nanowires (SiNWs) were determined via atomic force microscopy bending experiments and nonlinear finite element analysis. In the native SiNWs, sigma(f) in the Si was comparable to the theoretical strength of Si < 111 >, approximate to 22 GPa. In the oxidized SiNWs, sigma(f) in the SiO2 was comparable to the theoretical strength of SiO2, approximate to 6 to 12 GPa. The results indicate a change in the failure mechanism between native SiNWs, in which fracture originated via inter-atomic bond breaking or atomic-scale defects in the Si, and oxidized SiNWs, in which fracture initiated from surface roughness or nano-scale defects in the SiO2.