Silicon nanowire: A new shape of crystalline silicon

Silicon nanowires have been synthesized by using a high-temperature laser ablation method. Transmission electron microscopic investigation shows that the nanowires are crystalline Si, and have diameters ranging from 3 to 43 nm and lengths up to a few hundreds μm. Raman scattering spectrum shows an asymmetric peak at the same position as that of bulk crystalline silicon. The x-ray diffraction revealed an important contribution from surface oxide. This is due to the high surface-to-volume ratio. Visible photoluminescence (PL) was observed in nanowires with sub-5 nm diameter.