AVS 53rd International Symposium
    Surface Science Thursday Sessions
       Session SS1-ThA

Paper SS1-ThA9
Oxygen-induced Surface Structures of Nb(110) Studied by LEED, AES and STM

Thursday, November 16, 2006, 4:40 pm, Room 2002

Session: Reactivity of Oxide Surfaces II
Presenter: B. An, AIST, Japan
Authors: B. An, AIST, Japan
S. Fukuyama, AIST, Japan
K. Yokogawa, AIST, Japan
Correspondent: Click to Email
Nb has attracted a great attention as a superconductive material and a hydrogen storage material; however, the material performance of Nb is extremely sensitive to surface oxides. Thus, the interaction of oxygen with Nb surface has been extensively studied by LEED-AES, XPS and EELS. Recently, we have studied the clean and oxygen-induced surface structures of Nb(100)@footnote 1@ and Nb(111)@footnote 2@ by STM with atomic resolution. In this study, we present the surface structures of Nb(110) formed during thermal cleaning in UHV and oxidation in low-pressure oxygen at 300 and 900 K by combined LEED, AES and STM. A quasi-periodically arranged sticklike structure, and the (3x1)-O, c(6x2)-O and clean (1x1) structures are sequentially observed on the Nb(110) surface at atomic resolution during thermal cleaning in UHV at temperatures from 1970 to 2500 K. At 300 K, the clean (1x1) surface is sequentially oxidized into the c(6x2)-O and (3x1)-O structures and the amorphous oxides in oxygen. At 900 K, the clean (1x1) surface is sequentially oxidized into the c(6x2)-O and sticklike structures in oxygen. The c(6x2)-O and (3x1)-O structures result from oxygen chemisorption and the sticklike structure results from the epitaxial growth of NbO@sub x@ oxide on Nb(110) surface. Atomic models for these oxygen-induced structures and the atomic-scale oxidation processes of the Nb(110) surface at 300 and 900 K are discussed. @FootnoteText@ @footnote 1@ B. An et al., Phys. Rev. B 68, 115423 (2003).@footnote 2@ B. An et al., 13th International Conference on Scanning Tunneling Microscopy/Spectroscopy and Related Techniques (STM2005), Abstracts, Sapporo, Japan, July 3-8, 2005, p. 81.