Radical-mediated adsorption: Ozone oxidation of passivated silicon

We report first-principles molecular dynamics calculations on the initial oxidation of hydrogen-passivated Si{0 0 1} by ozone (O3). We observe an intriguing radical-mediated adsorption mechanism, archetypal of a class not reported in the literature so far. Singlet ozone abstracts one hydrogen atom to form a short-lived hydrotrioxy radical (HO3), before dissociating into surface hydroxyl (OH) and gas-phase O2. Vibrational and electronic analysis of the hydrotrioxy species confirms the genuine radical nature of the reaction intermediate.