Large-scale synthesis, characterization and photoluminescence properties of amorphous silica nanowires by thermal evaporation of silicon monoxide

A single step non-catalytic process based on thermal evaporation of silicon monoxide has been established for large-scale synthesis of silica nanowires. Scanning electron microscopy, high-resolution transmission electron microscopy equipped with energy dispersive X-ray spectrometry (EDAX), X-ray diffractometry were used to characterize the morphology and structure of the material. The as-synthesized nanowires had amorphous structures with diameters in the range 30–100 nm and hundreds of micrometers in length. The EDAX analysis revealed that the nanowires consisted of mainly two elements Si and O in an atomic ratio of approximately 1:2 corresponding to silicon dioxide. Photoluminescence spectra of the silica nanowires showed strong blue emission around 393 nm. Nucleation and growth of silica nanowires has been discussed on the basis of tiny oxide cluster formation that acts as nucleation centers for the nanowires growth.