Oxygen-deficient SnO2(1 1 0): a STM, LEED and XPS study

The reconstruction process of SnO2(1 1 0) was investigated by scanning tunneling microscopy (STM), low energy electron diffraction (LEED) and X-ray photoelectron spectroscopy (XPS). The high-temperature 1×1 reconstruction could be identified as an intermediate face, transferable either to the 1×2 surface by annealing to higher temperature or back to the 4×1 reconstruction by annealing again at lower temperature. In this way, a new method to prepare well-ordered 4×1 terminated surfaces is introduced and the O/Sn ratio as well as the core-level positions of Sn 3d and O 1s were traced by XPS over a temperature range of 700–1200 K on freshly sputtered and on low-temperature long-time annealed SnO2(1 1 0). STM images of the 1×1 surface show a new structure of in-plane oxygen, ordered locally in zigzag rows that contribute to the LEED pattern as a very diffuse 2×1 intensity.