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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
online
"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)
online
Joerg
Gebauer, last revised 04/07/02
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