Morphology and Atomic Structure of Anatase TiO2(101) Surfaces of Natural and Synthetic Crystals

Abstract

The (101) surface of three different anatase TiO2 crystal samples is investigated using noncontact atomic force microscopy (NC-AFM). For all samples, the overall surface morphology is stable and exhibits only minor variations in roughness after preparation. Samples reproducibly exhibit small metastable defects that appear either as protrusions or depressions, depending on the nature of the tip-terminating cluster. A comparison of atomically resolved images acquired in the two consistently observed complementary contrast modes to a surface structure model facilitates the tentative identification of surface atomic sites and defect sites.