A Novel Route to the Synthesis of Silica Nanowires without a Metal Catalyst at Room Temperature by Chemical Vapor Deposition

Silica nanowires were synthesized by employing inherent directionality of chemical vapor reaction between bis(ethylmethylamino)-silane (H2Si[N(C2H5)(CH3)](2)) precursor and water, without a metal catalyst at room temperature. The difference in the oxidation reactivity between Si-H and Si-N bonds with water leads to the formation of silica nanowires. The mean diameter and length of the silica nanowires grown for 10 min were 60-80 nm and 1.9 mu m, respectively. Transmission electron microscopy revealed that the obtained nanowires had the concave tip, differing from other silica nanowires produced by a conventional vapor-liquid-solid method, and were amorphous. Energy dispersive X-ray spectroscopy, Fourier transform infrared, and X-ray photoelectron spectroscopy results also proved that the nanowires have a dose composition to stoichiometric SiO2. Silica nanowires were successfully synthesized on a poly(ethylene terephthalate) film. The nanowires can emit strong blue light and ultraviolet light under excitation at 266 nm.