Self‐Assembly of SiO₂ Nanowires and Si Microwires into Hierarchical Heterostructures on a Large Scale

Novel hierarchical heterostructures made of Si core microwires covered by dense, aligned SiO2 nanowires that form multiple junctions to the cores, have been synthesized on a large scale (see Figure). The Si wires are single crystals with a diameter of ∼ 1–3 μm, whereas the SiO2 nanowires are amorphous with a diameter of ∼ 30–80 nm. The materials are envisaged as becoming important for optical fibers, low-dimensional waveguides, scanning near-field optical microscopes, and high-bandwidth optical signal processing devices.