ATOMIC-LEVEL STRUCTURE OF TIO2(110) AS A FUNCTION OF SURFACE OXYGEN COVERAGE

The surface structure of TiO2(110) has been investigated using scanning tunneling microscopy. Both (1 x 1) and (1 X 2) regions are observed on the vacuum annealed surface. Further oxygen can be absorbed to create highly elongated nuclei along the [110] direction. These coalesce at saturation coverage to generate a superstructure of 35 Angstrom periodicity with local c(2 X 1) structure rather than a (1 X 1) phase. Oxygen desorption from this saturation phase is highly anisotropic, suggesting that not all oxygens are bound with the same energy. These structural details may shed light on the complex surface chemistry of TiO2.