Low-Cost, Large-Scale, and Facile Production of Si Nanowires Exhibiting Enhanced Third-Order Optical Nonlinearity

A facile method for the low-cost and large-scale production of silicon nanowires has been developed. Silicon powders were subjected to sequential metal plating and metal-assisted chemical etching, resulting in well-defined silicon nanowires. The morphology and structure of the silicon nanowires were investigated, revealing that single-crystal silicon nanowires with average diameters of 79 ± 35 nm and length more than 10 μm can be fabricated. The silicon nanowires show excellent third-order nonlinear optical properties, with a third-order susceptibility much larger than that of bulk silicon, porous silicon, and silicon nanocrystals embedded in SiO2.