Spectroscopy of Metal Adsorbates on the GaAs(110) Surface Studied with the Scanning Tunneling Microscope


The geometric and electronic structure of metal adsorbates on cleaved GaAs(110) surfaces is studied with the scanning tunneling microscope. For the metals Sb and Bi, an ordered monolayer is formed, although in the case of Bi a series of misfit dislocations appear in the overlayer. In the case of Au, individual atoms are observed on the surface, forming clusters at higher metal coverage. Spectroscopic measurements reveal the presence of a state within the GaAs band gap. This state is observed near individual metal adsorbates (for Au and Sb), and near the edge of metal terraces (for Sb and Bi). The observed state is responsible for determining the position of the Fermi-level at the surface.


  1. 1.

    For a review, see L. J. Brillson, Surf. Sci. Rep. 2, 123 (1982).

    CAS  Article  Google Scholar 

  2. 2.

    G. Binnig and II. Rohrer, Helv. Phys. Acta 55, 726 (1982); Surf. Sci. 152/153, 17 (1985); Rev. Mod. Phys. 59, 615 (1987).

    CAS  Google Scholar 

  3. 3.

    P. Skeath, C. Y. Su, I. Lindau, and W. E. Spicer, J. Vac. Sci. Tech. 17, 874 (1980); P. Skeath, I. Lindau, C. Y. Su, and W. E. Spicer, J. Vac. Sci. Tech. 19, 556 (1981); P. Skeath, C. Y. Su, W. A. Harrison, I. Lindau, and W. E. Spicer, Phys. Rev. B 27, 6246 (1983).

    CAS  Article  Google Scholar 

  4. 4.

    J. Carelli and A. Kahn, Surf. Sci. 116, 380 (1982);

    CAS  Article  Google Scholar 

  5. 5.

    C. B. Duke, A. Paton, W. K. Ford, A. Kahn, and J. Carelli, Phys. Rev. B 26, 803 (1982).

    CAS  Article  Google Scholar 

  6. 6.

    R. M. Feenstra and P. Mårtensson, Phys. Rev. Lett. 61, 447 (1988); Proceeding of the 19th International Conference on the Physics of Semiconductors, DHN Ltd. (Warsaw, 1988).

    CAS  Article  Google Scholar 

  7. 7.

    P. Mårtensson and R. M. Feenstra, Phys. Rev. B. 39, 15 April 1989, to be published; J. Microscopy, to be published.

    Article  Google Scholar 

  8. 8.

    A. B. McClean, R. M. Feenstra, A. Taleb-Ibrahimi, and R. Ludeke, submitted to Phys. Rev. B.

  9. 9.

    R. Ludeke, A. Taleb-Ibrahimi, R. M. Feenstra, and A. B. McClean, submitted to J. Vac. Sci. Tech. B.

  10. 10.

    R. M. Feenstra, submitted to Phys. Rev. Lett.; submitted to J. Vac. Sci. Tech. B.

  11. 11.

    J. Van Laar and J. J. Scheer, Surf. Sci. 8, 342 (1967).

    Article  Google Scholar 

  12. 12.

    F. A. Cunnell and C. H. Gooch, J. Phys. Chem. Solids 15, 127 (1960).

    CAS  Article  Google Scholar 

  13. 13.

    F. Schäffler, R. Ludeke, A. Taleb-Ibrahimi, G. Hughes, and D. Rieger, Phys. Rev. B36, 1328 (1987); J. Vac. Sci. Tech. B 5, 1048 (1987).

    Article  Google Scholar 

  14. 14.

    R. M. Feenstra and J. A. Stroscio, J. Vac. Sci. Tech. B 5, 923 (1987). For perfectly flat band conditions, tunneling spectra from the clean p -GaAs surfaces actually display nonzero conductivity in the gap region due to tunneling into empty states at the top of the valence band. That component of the conductivity is not seen in Fig. 1(a) because that spectrum was obtained from a portion of the surface with band bending of ~ 0.03 eV.

    CAS  Article  Google Scholar 

  15. 15.

    J. E. Klepeis and W. A. Harrison, submitted to J. Vac. Sci. Tech. B.

  16. 16.

    I. Lefebvre, M. Lannoo, and G. Allan, to be published.

  17. 17.

    W. Mönch, Europhys. Lett. 7, 275 (1988).

    Article  Google Scholar 

  18. 18.

    W. E. Spicer, Z. Lilietal-Weber, E. Weber, N. Newman, T. Kendelewicz, R. Cao, C. McCants, P. Mahowald, K. Miyano, and I. Lindau, J. Vac. Sci. Tech. B 6, 1245 (1988).

    CAS  Article  Google Scholar 

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Feenstra, R.M., Mårtensson, P. & Ludeke, R. Spectroscopy of Metal Adsorbates on the GaAs(110) Surface Studied with the Scanning Tunneling Microscope. MRS Online Proceedings Library 139, 15–24 (1988). https://doi.org/10.1557/PROC-139-15

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