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Scanning Tunneling Microscopy


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Te donor in GaAs

Scanning Tunneling Microscopy

Scanning tunneling microscopy is a powerful tool for the study of atomic-scale properties in solids. Defects can be studied atom by atom; interface roughness can be studied layer by layer, surface segregation can be studied atom by atom. For example, the location of individual dopant atoms can be determined.

We employ "Cross-Sectional Scanning Tunneling Microscopy" (XSTM) to investigate the geometric and electronic structure of cleaved semiconductor surfaces. Emphasis is put on the study of defects (e.g. vacancies, dopants, or dislocations), quantum-well-structures, super-lattices, and interfaces in various semiconductor systems. We collaborate closely with the Salmeron AFM/STM group at LBNL.

Examples of XSTM studies are investigations of defects in GaAs and of heterostructure interfaces. We also investigated the STM contrast of the GaAs (110) surface in more detail.


Some publications of the STM team

    "Scanning Tunneling Microscopy Studies of Si Donors in GaAs"
    J.F. Zheng, X. Liu, N. Newman, E.R. Weber, D.F. Ogletree, and M. Salmeron, Phys. Rev. Lett. 72, 1490 (1994)

    "Interface Segregation and Clustering in Strained-Layer InGaAs/GaAs Heterostructures Studied by Cross-Sectional Scanning Tunneling Microscopy"
    J.F. Zheng, J.D. Walker, M.B. Salmeron, and E.R. Weber, Phys. Rev. Lett. 72, 2414 (1994)

    "Atomic resolution studies of dopant effects on intermixing in AlAs/GaAs short period superlattices"
    J.F. Zheng, M. Salmeron and E.R. Weber, Solid State Commun. 93, 419 (1995)

    "Scanning Tunneling Microscopy of Defects in Semiconductors"
    N. D. Jäger and E. R. Weber
    in Identification of Defects in Semiconductors II; Vol. 51 B , edited by M. Stavola (Academic Press, Boston, 1999), p. 261-296.

    "Low temperature ultrahigh vacuum cross-sectional scanning tunneling microscope for luminescence measurements"
    Yoonho Khang; Yeonjoon Park; Salmeron, M.; Weber, E.R., Review of Scientific Instruments, Dec. 1999, vol.70, (no.12):4595-9

    "Interpretation of GaAs(110) scanning tunneling microscopy image contrast by the symmetry of the surface Bloch wave functions"
    N. D. Jäger, E. R. Weber, M. Salmeron, Journal of Vacuum Science & Technology B19, 511 (2001)

Joerg Gebauer, last revised 04/07/02   





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