Synthesis of silica nanowires by active oxidation of silicon substrates.

Amorphous silica nanowires have been produced by thermal annealing of Si/SiO 2 /Ni substrate structures at 900 °C under an atmosphere of hexamethyldisilazane (HMDS) and hydrogen (H 2 ). The wires have diameter ranging from 35 to 55 nm, which are controlled by the Ni particle size. It is demonstrated that the growth occurs through vapor-liquid-solid mechanisms, and it is proposed that the vapor source is volatile SiO generated from the etching of the Si substrate through active oxidation reactions. The role of the HMDS-H 2 atmosphere in promoting such reactions is discussed.