Density functional theory investigation of molecular oxygen interacting with Si(1 0 0)-(2 × 1)

Density functional theory is used to investigate possible chemical reaction pathways for O2 molecule dissociation onto a Si(1 0 0)-(2 × 1) surface and further incorporation of its oxygen atoms into Si–Si bonds. It is shown that exothermic barrierless dissociation is feasible and requires the presence of two silicon surface dangling bonds. Therefore, oxygen atoms tend to separate and further incorporate into the backbonds of different surface silicon atoms. This process takes place either within the same dimer unit or within two neighbouring dimer units. Preliminary results, pathways and associated energetics (including activation barriers) are presented and discussed at the light of previous first principles calculations from the literature and more recent in situ infrared experimental data. Specifically, new directions are given to understand the formation of silanone surface configuration.