Intrinsic and External Factors Influencing the Ultralarge Elasticity of Silicon Nanowires

Silicon remains the cornerstone in today's immense semiconductor industry. At the nanoscale, silicon could exhibit large elasticity, which holds great potential for flexible electronics and 'elastic strain engineering'. Here, we report the influence of crystalline orientation, specimen size, strain rate, and electron beam irradiation on the ultra large (>10%) elastic deformation and fracture behavior of VLS-grown single crystalline silicon nanowires (Si NWs), and demonstrated that Si NWs grown along <110> directions exhibited greater strength and deformability than those along <111>. As the specimen diameters decreased, the fracture strength and strain of Si NWs doubled, and smaller specimens tended to 'fly away' upon fracture due to the substantial accumulated elastic potential energy. Results indicate that the intricate mechanical properties of Si NWs are susceptible to multiple intrinsic and extrinsic factors. By strategically manipulating the specific variables, the mechanical robustness and deformation tolerance of Si NW-based electronic devices can be tailored.