The adsorption behaviour of O2 on the clean Si(110) surface in the early stage

This Letter reports on the early stage of adsorption of O2 on the clean Si(110) surface, showing a prominent 5×1 reconstruction, in ultrahigh vacuum at 300 K. Auger electron spectroscopy (AES) and low energy electron diffraction (LEED) have been used to monitor this solid-gas reaction. Careful measurements of the normalized oxygen Auger signal in the low exposure region reveal, for the first time, a remarkably fast adsorption of O2 up to 0.15 monolayer of oxygen, the initial sticking probability being about 1. The LEED measurements suggest that those surface sites which constitute the additional higher order reconstructions, are highly reactive.