Study of p-diaminobenzene Adsorption on Au(111) by Scanning Tunneling Microscopy

ORAL

Abstract

From the well-defined conductivity obtained for various individual diamino-substituted molecules spanning two gold contacts, as well as from theoretical analysis [1], researchers have suggested that amines adsorb preferentially to coordinatively unsaturated surface Au atoms through the N lone pair. To understand the nature of the amine binding, we have applied ultrahigh vacuum scanning tunneling microscope (STM) to investigate the adsorption of p-diaminobenzene molecules on the reconstructed Au(111) surface. The STM topography images (taken at 4 K) show that the molecules adsorb preferentially to step edges, corresponding to sites of reduced Au atom coordination. The adsorbed molecules are found to display a distinctive orientation along the step edges. The two-lobe topographic structure of each molecule seen by STM is compatible with the previously calculated charge density of the HOMO level. [1] L. Venkataraman at el., Nano Lett. 7, 502 (2007).

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Authors

  • Hui Zhou

    • Columbia University, Department of Physics

  • Zonghai Hu

    • Columbia University, Department of Physics

  • Daejin Eom

    • Columbia University
    • Columbia University, Department of Chemistry

  • Kwang Rim

    • Columbia University, Department of Chemistry

  • Li Liu

    • Columbia University, Department of Chemistry
    • Columbia University

  • George Flynn

    • Columbia University, Department of Chemistry
    • Columbia University

  • Latha Venkataraman

    • Columbia University, Department of Applied Physics
    • Dept. of Applied Physics, Columbia Univ.
    • Columbia University

  • Alberto Morgante

    • Laboratorio TASC-INFM

  • Tony Heinz

    • Columbia University, Department of Physics
    • Columbia University