Identification of the initial-stage oxidation products on Si(111)-(7x7)

Abstract

Density functional theory calculations are used to study the initial-stage adsorption of O(2) molecules on the Si(111)-(7 X 7) surface. Contrary to experimental suggestions, we find no evidence of metastable O(2) molecular states on this surface, i.e., O(2) molecules dissociate spontaneously without any barrier. Our electronic and vibrational analysis reveals that the resulting atomic-oxygen products can explain the "molecular" features reported in previous experiments.