High reactivity of silicon suboxide clusters

The recent silicon-oxide-assisted formation of Si nanostructures has been studied based on quantum-mechanical calculations of ${\mathrm{Si}}_{n}{\mathrm{O}}_{m}$ $(n,m=1--8)$ clusters. We found that (1) energetically the most favorable small silicon-oxide clusters have O atomic ratios at around 0.6, and (2) remarkably high reactivity at the Si atoms exists in silicon suboxide ${\mathrm{Si}}_{n}{\mathrm{O}}_{m}$ clusters with $2n>m.$ The results show that the formation of Si-Si bonds is preferred and thus facilitates the nucleation of Si nanostructures when silicon suboxide clusters come together or stack to a substrate.