Low-dimensional NbO structures on the Nb(110) surface: scanning   tunneling microscopy, electron spectroscopy and diffraction
  X-ray photoelectron spectroscopy and diffraction (XPS, XPD) and scanning tunneling microscopy (STM) have been used for study of NbOx-structures on the Nb(110) surface. It is shown that niobium atoms are ordered to form a two-dimensional superstructure with equidistant spacing between the chains of niobium atoms. Chemical shifts of Nb3d- and O1s-levels demonstrate that the oxide layer corresponds to niobium monoxide NbO and the most part of oxygen in chemisorbed state is localized on the surface. A model of quasi-ordered structure of NbO on the Nb(110) surface is proposed. 
A.S. Razinkin, E.V. Shalaeva and M.V. Kuznetsov