A model of the NbOx≈1 nanocrystals tiling a Nb(110) surface annealed in UHV

被引：34

作者：

Arfaoui, I

Cousty, J ^{[1
]}

Guillot, C

机构：

[1] CEA, Direct Sci Mat, Serv Phys & Chim Surfaces & Interfaces, Ctr Etud Saclay, F-91191 Gif Sur Yvette, France

[2] CEA, Direct Sci Mat, Serv Etud Acclerateurs, Ctr Etud Saclay, F-91191 Gif Sur Yvette, France

来源：

SURFACE SCIENCE | 2004年 / 557卷 / 1-3期

关键词：

niobium; single crystal surfaces; scanning tunneling rnicroscopy; synchrotron radiation photoelectron spectroscopy; interface states; surface stress; surface structure; morphology; roughness; and topography;

D O I：

10.1016/j.susc.2004.03.025

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

The layer covering a (1 1 0) face of Nb crystal annealed at 1500-2200 K in UHV has been studied by photoemission spectroscopy with synchrotron radiation and scanning tunneling microscopy (STM). This overlayer resulting from segregation of the oxygen dissolved in Nb bulk presents a Complex Structure with several kinds of Nb oxides. Analysis of photoemission spectra of 3d Nb core levels reveals that: (i) the oxide stoichiometry is mainly ranging from NbOxapproximate to1.2 to NbOxapproximate to0.8; (ii) the oxide thickness corresponds to 1.4+/-0.3 monolayer of Nb atoms. As observed in STM images, the structure of this oxide overlayer consists of a quasi-periodic arrangement of NbOxapproximate to1 nanocrystals. Each nanocrystal is characterized by a prominent stick formed by 10+/-1 egg-shaped bumps aligned along a close-packed NbO<1 1 0> direction. These bumps are related to Nb atoms adsorbed as a close-packed row on the outmost (1 1 1) oxygen plane of a NbO nanocrystal. and to chemical bonds involving these Nb atoms and the underlying atoms. The origin of such an atomic structure is discussed. (C) 2004 Elsevier B.V. All rights reserved.

引用

页码：119 / 128

页数：10

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