Catalytic synthesis of straight silicon nanowires over Fe containing silica gel substrates by chemical vapor deposition

Abstract

We report a new method to synthesize very straight silicon nanowires using a porous iron/SiO 2 gel as a template by thermal chemical vapor deposition at a temperature of about 500°C. Scanning electron microscopy, transmission electron microscopy and Raman scattering spectroscopy were used to characterize the samples. The results show that a large amount of straight Si nanowires with diameters of about 30 nm and lengths of about 1 μm was obtained. High-resolution transmission electron microscopy observation shows that microtwin defects lie in the straight silicon nanowires. Raman scattering from the nanowires shows a larger line width (about 15 cm −1) and a down-shifted (about 9 cm −1) peak as compared to that of bulk crystalline silicon.