The structure of the polar Sn-doped indium oxide (001) surface

Epitaxial Sn-doped In2O3 (ITO) thin films were grown using oxygen plasma-assisted molecular beam epitaxy (MBE) on (001) oriented Yttria Stabilized Zirconia. Low-energy-electron-diffraction shows that ITO (001) surface is oxygen terminated and has a c(1 x 1)-structure with p4g symmetry. Atomically-resolved Scanning Tunneling Microscopy suggests that surface oxygen atoms undergo dimerization; possible adsorption sites are identified. The density of surface oxygen depends on the Sn concentration and it is suggested that both, dimerization and doping stabilize the polar ITO (001) surface. (C) 2009 American Institute of Physics. [doi:10.1063/1.3275716]