Local surface structure and composition determination by low-energy electron microscopy and Monte Carlo simulation

ORAL

Abstract

It has been long pursued to accurately measure surface structure and composition with high temporal and spatial resolutions. Modern surface analytical techniques, however, either have to assume a homogeneous surface structure, or have only a very limited sensitivity to subsurface or chemical composition. We have developed a novel analysis technique to overcome these limitations [1-2]. We are able for the first time to measure a complete 3D composition map of the first three surface layers in real time by analyzing low-energy electron microscopy imaging intensity dynamically. We have demonstrated that a lateral spatial resolution of about 8.5 nm can be achieved to unravel the origin of the heterogeneous PdCu surface alloy grown on a Cu(001) substrate. A fundamental step-overgrowth mechanism has been identified to be responsible for the heterogeneity developing around steps, a generic mechanism relevant to many thin-film systems. Furthermore, Monte Carlo simulations indicate that the favorable NN Pd-Cu bonding is responsible for the heterogeneity in the PdCu system and not a slow diffusion process. [1] J. B. Hannon \textit{et al.}, Phys. Rev. Lett. 96, 246103(2006) [2] J. Sun\textit{ et al.}, Phys. Rev. B (scheduled for publication 15 Oct 2007)

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Authors

  • Jiebing Sun

    Univ. of New Hampshire

  • V.E. Guiseppe

    University of Connecticut, Univ. of New Hampshire, Sandia National Labs, IBM Research Center, PTB, TUNL, Petersburg Nuc. Phys. Inst., Yale Univ., U.S. Coast Guard Acad., Department of Physics, University of Connecticut, Storrs, CT 06269-3046, Physics Department, Carnegie Mellon University, Pittsburgh, PA 15213, Division of Proton Engineering Frontier Project, Korea Atomic Energy Research Institute, Daejeon, Korea, Department of Chemistry, Sogang University, Seoul, Korea, Materials Science Department, Brookhaven National Lab, Upton, NY 11973, Canadian Light Source, University of Saskatchewan, Saskatoon, Canada, Department of Physics, University of Connecticut, Storrs, CT 06269, RMD Inc., Watertown, MA, ALEM Associates, Boston, MA, Physics Department, University of Connecticut, Storrs, CT, University of South Dakota, LANL

  • V.E. Guiseppe

    University of Connecticut, Univ. of New Hampshire, Sandia National Labs, IBM Research Center, PTB, TUNL, Petersburg Nuc. Phys. Inst., Yale Univ., U.S. Coast Guard Acad., Department of Physics, University of Connecticut, Storrs, CT 06269-3046, Physics Department, Carnegie Mellon University, Pittsburgh, PA 15213, Division of Proton Engineering Frontier Project, Korea Atomic Energy Research Institute, Daejeon, Korea, Department of Chemistry, Sogang University, Seoul, Korea, Materials Science Department, Brookhaven National Lab, Upton, NY 11973, Canadian Light Source, University of Saskatchewan, Saskatoon, Canada, Department of Physics, University of Connecticut, Storrs, CT 06269, RMD Inc., Watertown, MA, ALEM Associates, Boston, MA, Physics Department, University of Connecticut, Storrs, CT, University of South Dakota, LANL

  • V.E. Guiseppe

    University of Connecticut, Univ. of New Hampshire, Sandia National Labs, IBM Research Center, PTB, TUNL, Petersburg Nuc. Phys. Inst., Yale Univ., U.S. Coast Guard Acad., Department of Physics, University of Connecticut, Storrs, CT 06269-3046, Physics Department, Carnegie Mellon University, Pittsburgh, PA 15213, Division of Proton Engineering Frontier Project, Korea Atomic Energy Research Institute, Daejeon, Korea, Department of Chemistry, Sogang University, Seoul, Korea, Materials Science Department, Brookhaven National Lab, Upton, NY 11973, Canadian Light Source, University of Saskatchewan, Saskatoon, Canada, Department of Physics, University of Connecticut, Storrs, CT 06269, RMD Inc., Watertown, MA, ALEM Associates, Boston, MA, Physics Department, University of Connecticut, Storrs, CT, University of South Dakota, LANL