Suboxide interface in disproportionating a-SiO studied by x-ray Raman scattering

The microscopic structure of disproportionating amorphous silicon monoxide is studied by inelastic x-ray scattering at the silicon L-II,L-III edge. This material arranges into nanocrystalline regions of Si embedded in amorphous SiO2 at proper annealing temperatures and in this work we demonstrate how the contribution of the suboxide interfaces between these regions can be extracted from the experimental data. The resulting near-edge spectra are analyzed in detail using a computational framework that combines molecular-dynamics simulations and density-functional theory calculations. The results indicate that the amount of silicon atoms with oxidation states between +1 and +3 is significant and depends strongly on the annealing temperature. Furthermore, the presented s, p, and d-type local densities of states (lDOS) demonstrate that the most significant differences are found in the p-type lDOS.