IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Surface Science Friday Sessions
       Session SS3-FrM

Paper SS3-FrM1
Structure and Electronic Properties of Planar and Faceted Ir(210)

Friday, November 2, 2001, 8:20 am, Room 122

Session: Clean and Adsorbed Surfaces
Presenter: I. Ermanoski, Rutgers, The State University of New Jersey
Authors: I. Ermanoski, Rutgers, The State University of New Jersey
M. Gladys, Rutgers, The State University of New Jersey
G.J. Jackson, Rutgers, The State University of New Jersey
T.E. Madey, Rutgers, The State University of New Jersey
J.E. Rowe, U.S. Army Research Office
Correspondent: Click to Email
The atomically rough Ir(210) surface is morphologically unstable: When Ir(210) is covered with more than 0.6 ML of oxygen and annealed, pyramidal facets develop on the initially planar surface. We have used a variety of methods to investigate the structure and electronic properties of planar and faceted Ir(210), including LEED, STM and high resolution soft X-ray photoelectron spectroscopy (SXPS) using synchrotron radiation. To prepare an oxygen-free faceted surface, we use catalytic CO oxidation at ~500 K to react the oxygen off the pre-prepared faceted surface. Cleanliness is verified both by AES and TPD. LEED and STM experiments show that the faceted surface is entirely covered with 3-sided pyramidal facets with dimensions of several nanometers. HRSXPS has been employed to investigate core-level features of all the surfaces mentioned. The Ir 4f7/2 core levels are fitted with Doniach-Sunjic lineshapes. Surface and bulk peak identifications are supported by measurements at different photon energies (different electron escape depths) and variable photoemission angles. All of the surface components (first, second and third layer peaks) are identified with core-level shifts positioned at higher binding energies with respect to the bulk. This result is in contrast to previous reports of binding energy inversion on Ir(100) and Ir(111) surfaces. The adsorption of oxygen onto the planar Ir(210) surface causes a suppression and shifting of the surface features. A comparison of planar and faceted surfaces reveals only minor differences in the SXPS core-level spectra. The effect of metallic overlayers on the morphological stability of Ir(210) will also be discussed. Supported by US DOE and ARO.