Transforming a thin silica layer into nanowires

In this paper, we report a very simple approach to transform a thin silica cap layer, formed by thermal oxidation on Si(001) substrates, into SiO 2 nanowires, i.e. treating the silica cap layer with ferrocene molecules, heating it up in argon flow and then exposing it to methane at ∼1000°C. During the heating process ferrocene molecules reacted with the silica surface through some chemical procedures and formed circular templates on the silica surface from which silica nanowires started to develop when exposed to methane. The nanowires so produced are amorphous, ∼15 nm in diameter and several hundred micrometres in length. Prolonged exposure to methane at this temperature transformed completely the silica cap layer into nanowires. This study provides a new method to fabricate silica nanowires on planar substrates.