Si₂ O_y (y = 1– 6) clusters: Models for oxidation of silicon surfaces and defect sites in bulk oxide materials

We studied the structure and bonding of a series of silicon oxide clusters, Si₃O_y (y = 1 – 6), using anion photoelectron spectroscopy and ab initio calculations. For y = 1 – 3 the clusters represent the sequential oxidation of Si₃, and provide structural models for the oxidation of silicon surfaces. For y = 4 – 6, the clusters contain a central Si in a tetrahedral bonding environment, suggesting the onset of the bulklike structure. Evidence is presented that suggests the Si₃ O₄ cluster (D_2d) may provide a structural model for oxygen-deficient defect sites in bulk SiO₂ materials.