Hydrogen-terminated Si Surfaces. Oxidation Reaction of Dangling Bonds on a Si(001)-2*1-H Surface.

Abstract

The oxidation reaction of an unpaired dangling bond (DB) and a DB atomic wire on a hydrogen-terminated Si(100) 2×1 surface was studied using an ultrahigh-vacuum scanning tunneling microscopy. We found that O2 molecules dissociated into atomic oxygen after reacting with DBs. The atomic oxygen oxidized also the bonds near DBs. The oxidation reaction was turned to be considerably enhanced at the DB atomic wire, compared with that at an unpaired DB. This suggests that the electron transfer to anti-bonding π orbital of O2 molecule depends on the local density of states at an unpaired DB and at a DB atomic wire.