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Transport of Adsorbed Species: Correlations with Concentration and Step Structure

  • Heribert Wagner
Part of the NATO Advanced Science Institutes Series book series (NSSB, volume 86)

Abstract

The thermally activated motion of adsorbed atoms on solid surfaces may be described by single hops over activation barriers separating adjacent adsorption sites. Field ion microscopyl is ideally suited to study this process on the well defined crystal planes of field emitter tips. Activation energy and pre-exponential factor of the diffusion coefficient for this random walk process are readily determined. The presence of adsorbed atoms on neighbouring adsorption sites gives rise to mutual interactions which affect the random walk of the individual atom. Changes of the substrate structure e.g. different crystal planes or steps and kinks also modify the diffusive motion by inserting different activation barriers. To some extend these influences can also be investigated by field ion microscopy. Due to the small extension of the crystal planes present on field emitter tips and the insufficient resolution for high adsorbate coverage field ion microscopy can not be employed to investigate diffusion caused by a concentration gradient or, in more general terms, by a chemical potential gradient. Unlike the random walk diffusion this process leads to a true mass transport over distances much larger than the individual jump distance.

Keywords

Work Function Auger Electron Spectroscopy Diffusion Profile Oxygen Coverage Step Density 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    D. W. Bassett, this volumeGoogle Scholar
  2. 2.
    H. P. Bonzel, this volumeGoogle Scholar
  3. 3.
    R. Butz and H. Wagner, Surface Sci. 63: 448 (1977)CrossRefGoogle Scholar
  4. 4.
    R. Butz and H. Wagner, Appl. Phys. 13: 37 (1977)CrossRefGoogle Scholar
  5. 5.
    R. Butz and H. Wagner, Abcdefg, in: “Proc. 7th Intern. Vacuum Congr. and 3rd Intern. Conf. on Solid Surfaces”, Vol. II, p. 1289 (Vienna, 1977 )Google Scholar
  6. 6.
    R. Butz and H. Wagner, Surface Sci. 87: 69 (1979)CrossRefGoogle Scholar
  7. 7.
    R. Butz and H. Wagner, Surface Sci. 87: 85 (1979)CrossRefGoogle Scholar
  8. 8.
    A. G. Fedorus, A.G. Naumovets and Yu.S. Vedula, Phys. Stat. Sol. (a) 13: 445 (1972)CrossRefGoogle Scholar
  9. 9.
    A. G. Naumovets and A.G. Fedorus, JETP 41: 587 (1976)Google Scholar
  10. 10.
    V. K. Medvedev and T.P. Smereka, Soviet Phys.-Solid State 16: 1046 (1974)Google Scholar
  11. 11.
    Yu. S. Vedula, A.T. Loburets and A.G. Naumovets, JETP 50: 391 (1980)Google Scholar
  12. 12.
    A. T. Loburets, A.G. Naumovets and Yu.S. Vedula, Surface Sci. in pressGoogle Scholar
  13. 13.
    H. Shelton, Phys. Rev. B 107: 1553 (1957)CrossRefGoogle Scholar
  14. 14.
    Yu. S. Vedula and A.G. Naumovets, in: “Poverkhnostnaya diffuziya i rastekanie (Surface Diffusion and Spreading)” ed. Ya.E. Geguzin ( Nauka, Moscow, 1969 ) p. 149.Google Scholar
  15. 15.
    G. A. Haas and R.E. Thomas, J. Appl. Phys. 34:3457 (1963) Surface Sci. 4: 64 (1966)Google Scholar
  16. 16.
    W. Thomas, Phil. Mag. 46: 82 (1898)Google Scholar
  17. 17.
    W. A. Zisman, Rev. Sci. Instr. 3: 367 (1932)CrossRefGoogle Scholar
  18. 18.
    R. Butz, in: “Jül-1314”, KFA Jülich (1976)Google Scholar
  19. 19.
    K. Besocke and S. Berger, in: “Proc. 7th Intern. Congr. and 3rd Intern. Conf. on Solid Surfaces”, Vol. II, p. 893 (Vienna 1977 ).Google Scholar
  20. 20.
    K. Besocke and H. Wagner, Phys. Rev. B 8: 4597 (1973)CrossRefGoogle Scholar
  21. 21.
    T. Engel, H. Niehus and E. Bauer, Surface Sci. 52: 237 (1975)CrossRefGoogle Scholar
  22. 22.
    J. Crank, “Mathematics of Diffusion”, McGraw-Hill, New York 1963.Google Scholar
  23. 23.
    T. M. Lu, G.C. Wang and M.G. Lagally, Surface Sci 92:133 (1980) and references thereinGoogle Scholar
  24. 24.
    M. Bowker and D.A. King, Surface Sci. 71:583 (1978) 72: 208 (1978)Google Scholar
  25. 25.
    H. Asada and Masuda, Surface Sci. 99: L429 (1980)CrossRefGoogle Scholar
  26. 26.
    W. Zwerger, Z. Phys. B 45:333 (1981); see also W. Zwerger, this volume.Google Scholar
  27. 27.
    E. Bauer, H. Poppa, G. Todd and P.R. Davis, J. Appl. Phys. 48: 3773 (1977)CrossRefGoogle Scholar
  28. 28.
    D. Paraschkevov, W. Schlenk, R.P. Bajpai and E. Bauer, in: “Proc. 7th Intern. Vacuum Congr. and 3rd Intern. Conf. on Solid Surfaces”,Vol. II, p. 1737 (Vienna, 1977 ).Google Scholar
  29. 29.
    E. Bauer, F. Bouczek, H. Poppa and G. Todd, Surface Sci. 53: 87 (1975)CrossRefGoogle Scholar
  30. 30.
    H. Wagner, in: “Springer Tracts in Modern Physics”, Vol. 85, Springer, Berlin, 1979.Google Scholar

Copyright information

© Plenum Press, New York 1983

Authors and Affiliations

  • Heribert Wagner
    • 1
  1. 1.Institut für Grenzflächenforschung und VakuumphysikKernforschungsanlage JülichJülichW.-Germany

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