Minimum stable height of Ag nano-islands on Si(111)7x7

ORAL

Abstract

The origin of a minimum stable Ag nano-island height of one bi-layer on top of the wetting layer has remained a long-standing mystery in the effort to understand mechanisms that control the growth of supported nanoscale metals. We present the results of synchrotron x-ray scattering studies which demonstrate that the interfacial energy, rather than previously suspected electron confinement effects, is responsible for the minimum island height. In situ measurements of x-ray reflectivity and crystal truncation rods reveal that the Ag nano-islands consume the wetting layer and are, therefore, tri-layers -- an effect that cannot be detected by scanning probe measurements. These experiments lead to an energy ``phase diagram'' that we propose to explain the existence of a minimum island height for supported nanoscale metals. Support from the National Science Foundation under grants DMR-0706278 and DGE-1069091 is gratefully acknowledged. The Advanced Photon Source Sector 6 beam-line at Argonne National Laboratory is supported by the US-DOE under Contract No. W-31-109-Eng-38.

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Authors

  • Yiyao Chen

    University of Missouri-Columbia, University of Missouri - Columbia

  • Mark Neubauer

    University of Missouri-Columbia, Southern Illinois University Carbondale, Indiana University, Purdue University, Argonne National Laboratory, University of Missouri, College of Physics Science, Qingda University, Qingdao, 266071, China, Indian Institute of Science, Bangalore, India, University of Massachusetts Amherst, Iowa State University, Technical University of Denmark, University of Missouri - Columbia, University of California - San Diego, La Jolla, CA 92093, Department of Physics, University of Missouri-Columbia, Columbia, Missouri 65211, Department of Physics and Astronomy, University of Missouri-Columbia, University of Missouri, Columbia, MO, Department of Physics and Department of Biochemistry, University of Missouri, Columbia, MO 65211, Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599-3290, Univ of Missouri - Columbia, Duke University, Shanghai Jiaotong University, Ames Laboratory, U.S. DOE, Texas Center of Superconductivity and the Department of Physics, University of Houston, Institute of Physics, Siberian Division, Russian Academy of Sciences, Krasnoyarsk, 66036, Russia, Oak Ridge National Laboratory, NIST Center for Neutron Research, MU Research Reactor, Ames Laboratory and Dep. of Physics and Astronomy, Iowa State University, AmesAmes Laboratory and Dep. of Physics and Astronomy, Iowa State University, HFIR, Oak Ridge National Laboratory, University of Illinois at Urbana-Champaign

  • Mark Neubauer

    University of Missouri-Columbia, Southern Illinois University Carbondale, Indiana University, Purdue University, Argonne National Laboratory, University of Missouri, College of Physics Science, Qingda University, Qingdao, 266071, China, Indian Institute of Science, Bangalore, India, University of Massachusetts Amherst, Iowa State University, Technical University of Denmark, University of Missouri - Columbia, University of California - San Diego, La Jolla, CA 92093, Department of Physics, University of Missouri-Columbia, Columbia, Missouri 65211, Department of Physics and Astronomy, University of Missouri-Columbia, University of Missouri, Columbia, MO, Department of Physics and Department of Biochemistry, University of Missouri, Columbia, MO 65211, Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599-3290, Univ of Missouri - Columbia, Duke University, Shanghai Jiaotong University, Ames Laboratory, U.S. DOE, Texas Center of Superconductivity and the Department of Physics, University of Houston, Institute of Physics, Siberian Division, Russian Academy of Sciences, Krasnoyarsk, 66036, Russia, Oak Ridge National Laboratory, NIST Center for Neutron Research, MU Research Reactor, Ames Laboratory and Dep. of Physics and Astronomy, Iowa State University, AmesAmes Laboratory and Dep. of Physics and Astronomy, Iowa State University, HFIR, Oak Ridge National Laboratory, University of Illinois at Urbana-Champaign

  • Mark Neubauer

    University of Missouri-Columbia, Southern Illinois University Carbondale, Indiana University, Purdue University, Argonne National Laboratory, University of Missouri, College of Physics Science, Qingda University, Qingdao, 266071, China, Indian Institute of Science, Bangalore, India, University of Massachusetts Amherst, Iowa State University, Technical University of Denmark, University of Missouri - Columbia, University of California - San Diego, La Jolla, CA 92093, Department of Physics, University of Missouri-Columbia, Columbia, Missouri 65211, Department of Physics and Astronomy, University of Missouri-Columbia, University of Missouri, Columbia, MO, Department of Physics and Department of Biochemistry, University of Missouri, Columbia, MO 65211, Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599-3290, Univ of Missouri - Columbia, Duke University, Shanghai Jiaotong University, Ames Laboratory, U.S. DOE, Texas Center of Superconductivity and the Department of Physics, University of Houston, Institute of Physics, Siberian Division, Russian Academy of Sciences, Krasnoyarsk, 66036, Russia, Oak Ridge National Laboratory, NIST Center for Neutron Research, MU Research Reactor, Ames Laboratory and Dep. of Physics and Astronomy, Iowa State University, AmesAmes Laboratory and Dep. of Physics and Astronomy, Iowa State University, HFIR, Oak Ridge National Laboratory, University of Illinois at Urbana-Champaign