Local Work Function Approximation at Tip Induced Surface Vacancies by STM

POSTER

Abstract

Local surface work functions are important for many surface interactions including surface chemistry, site-specific adsorbate binding, and macromolecule self-assembly. The scanning tunneling microscope can act as a probe of the local work function by measurement of resonances that occur in the field-emission regime, which are Stark-shifted image potential resonances. The energetic positions of field emission resonances are extracted from bias dependent topographic sequences. Using this technique, surface regions with step edges, and surface vacancies created by controlled probe vertical manipulations, had their field-emission resonance energies measured throughout the imaged regions. The extracted resonance energies were fit by Gundlach's equation resulting in reasonable approximations for local surface work function, probe work function, and absolute probe height. The induced surface vacancies are interesting, considering industrial approaches to nanoindentation, with use for independent determination of the work functions for these nearly zero-dimensional objects.

Authors

  • Andrew R. Dilullo

    Ohio University, Nanoscale and Quantum Phenomena Institute, Department of Physics and Astronomy, Ohio University, Athens, Ohio, NQPI, and Dept of Physics \& Astronomy, Ohio University

  • Kurt Baughman

    Center for Nanoscale Materials, Argonne National Lab, Argonne, Illinois, Department of Physics and Astronomy, Ohio University, Athens, Ohio, Ohio University, Los Alamos Nationa Laboratory, National Taiwan University, University of Hamburg, Trinity College, Dublin, Serbian Academy of Sciences and Arts, Institute for Multidisciplinary Research, University of Belgrade, National High Magnetic Field Laboratory, Brookhaven National Laboratory, The University of Akron, NQPI, Physics and Astronomy Dept., Ohio University, GNS \& MANA Satellite, CEMES, CNRS, IMRE, A*STAR, Nanoscale and Quantum Phenomena Institute (NQPI), Physics and Astronomy Dept., Ohio University, Nanoscale and Quantum Phenomena Institute, and Department of Physics \& Astronomy, Ohio University, Athens, OH 45701, CEMES, CNRS, Toulouse, France, Nanoscale and Quantum Phenomena Institute, and Department of Physics \& Astronomy, Ohio University, Athens, OH, NQPI, and Department of Physics \& Astronomy, Ohio University, Athens, OH, NQPI Dept of Physics and astronomy Ohio University, Naval Research Labs, Washington DC 20375, John Carroll University, Lawrence Livermore National Laboratory, The Ohio State University Department of Physics, Nanoscale and Quantum Phenomena Institute, Department of Physics and Astronomy, Ohio University, Athens, Ohio, Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, National High Magnetic Field Laboratory, Tallahassee, University of Wisconsin Oshkosh, Wittenberg University, NQPI, Ohio University; CNM Argonne National Laboratory, APS, CNM, Argonne National Laboratory, Ohio University, Athens 45701, USA, None, Dept. of Physics, Hiram College, Physics Department, Cleveland State University, Flash Center for Computational Science, University of Chicago, Center for Energy Research, University of California San Diego; Lawrence Livermore National Laboratory, Ohio Northern University, Ohio University Zanesville

  • Kurt Baughman

    Center for Nanoscale Materials, Argonne National Lab, Argonne, Illinois, Department of Physics and Astronomy, Ohio University, Athens, Ohio, Ohio University, Los Alamos Nationa Laboratory, National Taiwan University, University of Hamburg, Trinity College, Dublin, Serbian Academy of Sciences and Arts, Institute for Multidisciplinary Research, University of Belgrade, National High Magnetic Field Laboratory, Brookhaven National Laboratory, The University of Akron, NQPI, Physics and Astronomy Dept., Ohio University, GNS \& MANA Satellite, CEMES, CNRS, IMRE, A*STAR, Nanoscale and Quantum Phenomena Institute (NQPI), Physics and Astronomy Dept., Ohio University, Nanoscale and Quantum Phenomena Institute, and Department of Physics \& Astronomy, Ohio University, Athens, OH 45701, CEMES, CNRS, Toulouse, France, Nanoscale and Quantum Phenomena Institute, and Department of Physics \& Astronomy, Ohio University, Athens, OH, NQPI, and Department of Physics \& Astronomy, Ohio University, Athens, OH, NQPI Dept of Physics and astronomy Ohio University, Naval Research Labs, Washington DC 20375, John Carroll University, Lawrence Livermore National Laboratory, The Ohio State University Department of Physics, Nanoscale and Quantum Phenomena Institute, Department of Physics and Astronomy, Ohio University, Athens, Ohio, Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, National High Magnetic Field Laboratory, Tallahassee, University of Wisconsin Oshkosh, Wittenberg University, NQPI, Ohio University; CNM Argonne National Laboratory, APS, CNM, Argonne National Laboratory, Ohio University, Athens 45701, USA, None, Dept. of Physics, Hiram College, Physics Department, Cleveland State University, Flash Center for Computational Science, University of Chicago, Center for Energy Research, University of California San Diego; Lawrence Livermore National Laboratory, Ohio Northern University, Ohio University Zanesville