NONSTOICHIOMETRY ON TIO2(110) AND CU-TIO2 INTERFACES

A number of reconstructions have been observed on the (110) surface of TiO2 in the rutile modification that accommodates oxygen deficiency. We present atomically resolved scanning tunneling microscope images th at describe a new reconstruction with (3X2) symmetry. A model for the observed reconstruction is discussed where this symmetry is achieved b y removing 1/3 or 2/3 of the oxygen in the bridging oxygen rows such t hat a shift in position of missing oxygen by one lattice space vector along the [001] direction occurs in every second row. This structure c ontrasts those reported previously in which entire rows are modified o r removed. Furthermore, nanometer-sized Cu islands on TiO2(110) surfac es fabricated by vapor deposition onto TiO2 at 200 degrees C were stud ied by conventional and high-resolution transmission electron microsco py (TEM). Our TEM studies show that Cu forms faceted islands (40 nm in width) on the surface with the orientation relationship given by Cu{1 10}parallel to TiO2(110) and Cu[001]parallel to TiO2[1(1) over bar 0]. The orientation relationship differs from that resulting from room te mperature deposition onto stoichiometric surfaces. (C) 1998 American V acuum Society.