Preparation and characterization of amorphous SiOx nanowires

Large-scale synthesis of amorphous silicon oxide nanowires (SiONWs) was achieved by using simple physical evaporation of the mixture of silica xerogel containing Fe nanoparticles and silicon powder. Transmission electron microscopy (TEM) observations showed that the amorphous SiONWs have a length of up to several tens of micrometers and a diameter of 10–40 nm. Energy-dispersed X-ray spectrometry (EDX) analysis revealed that the SiONWs consist of Si and O elements in atomic ratio approximately to 1:1.4. Different morphologies of nanowires such as straight, smoothly curved, braided and helical shapes were observed. The formation process of SiONWs was closely related to the VLS growth mechanism. Raman scattering spectrum of amorphous SiONWs showed that there is an asymmetric, broadened linewidth Raman peak at 502 cm−1 greatly different from that of bulk SiO2 non-crystalline solids.