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

We report a new method to synthesize very straight silicon nanowires using a porous iron/SiO2 gel as a template by thermal chemical vapor deposition a t a temperature of about 500 degreesC. Scanning electron microscopy, transm ission electron microscopy and Raman scattering spectroscopy were used to c haracterize the samples. The results show that a large amount of straight S i nanowires with diameters of about 30 nm and lengths of about 1 mum was ob tained. High-resolution transmission electron microscopy observation shows that microtwin defects lie in the straight silicon nanowires. Raman scatter ing from the nanowires shows a larger line width (about 15 cm(-1)) and a do wn-shifted (about 9 cm(-1)) peak as compared to that of bulk crystalline si licon. (C) 2001 Elsevier Science B.V. All rights reserved.