PREPARATION OF SiO2 HIERARCHICAL NANOSTRUCTURE VIA CATALYST-FREE THERMAL EVAPORATION METHOD

A novel hierarchical nanostructure of SiO2 nanowires standing on SiO2 microwires was synthesized through a catalyst-free thermal evaporation method in nitrogen atmosphere. The SiO2 nanowires have an average diameter of 100 nm and length of 2 mu m, while the diameter of the SiO2 microwires is around 10 mu m and the length is hundreds of micrometers. The photoluminescence spectrum of the SiO2 hierarchical nanostructure shows stable blue and green emission at 442 nm and 533 nm, respectively. An oxygen-assisted three-step growth mechanism was suggested to interpret the growth of the SiO2 hierarchical nanostructure.