Ta2O5 nanowires, nanotubes, and Ta2O5/SiO2 core-shelled structures: from growth to material characterization

One-dimensional polycrystalline Ta2O5 nanostructures are synthesized by the annealing of the SiO2 nanowires at 950°C in a reductive Ta vapor ambiance. The formation mechanism of Ta2O5 nanostructures is discussed and illustrated in detail. The nucleation and grain growth of Ta2O5 crystals were investigated during the formation of the SiO2/Ta2O5 core-shelled structures. The diffusion-controlled growth is suggested to be the rate-determining step for the diffusion of the Ta atoms through the ash layer to react with O atoms and substitute Si atoms.