Growth of amorphous SiO2 nano-wires on pre-oxidized silicon substrate via chemical vapor deposition

Abstract

Without an additional silicon source, amorphous SiO2 nano-wires were grown on the pre-oxidized silicon substrate with the assistance of Ni-based catalyst under ambient pressure. The as-grown amorphous SiO2 nano-wires were characterized by X-ray diffraction, scanning electron microscopy, high resolution transmission electron microscopy (HRTEM) and selected area diffraction. The micro-region chemical composition investigation on the as-grown amorphous SiO2 nano-wires was carried out using X-ray energy dispersion spectroscopy (EDS) on the HRTEM. The present work focuses on the formation of atomic H on the surface of pure zinc powder by introducing moisture (N2+H2O) into the furnace at high temperature. The growth mechanism has been discussed and attributed to the vapor–liquid–solid (VLS) mechanism instead of the adopted solid–liquid–solid (SLS) mechanism owing to the observed evidence of an etching reaction of atomic H at the SiO2 buffer layer and/or that of H at the Si substrate to form a gaseous hydro-silicon radical (SiHx) that is then transported to the growth sites. The intrinsic luminescent behavior of the amorphous SiO2 nano-wires in the range of 350–430nm was also reported and discussed. These results provide an alternative and simple procedure for nanostructures growth, which will be helpful to understand the growth mechanism of one dimensional SiO2 nanostructures.