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@PHDTHESIS{Blab:172749,
author = {Blab, Marcus},
title = {{L}adungstransportmessungen an {S}i(111) {O}berflächen mit
einem {M}ultispitzen-{R}astertunnelmikroskop},
volume = {93},
school = {RWTH Aachen},
type = {Dissertation},
address = {Jülich},
publisher = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
reportid = {FZJ-2014-06192},
isbn = {978-3-89336-997-3},
series = {Schriften des Forschungszentrums Jülich. Reihe
Schlüsseltechnologien / Key Technologies},
pages = {XVI, 181 Seiten},
year = {2014},
note = {Dissertation, RWTH Aachen, 2014},
abstract = {This work concernes with the characterization and further
development of a multitip scanning tunneling microscope and
charge transport measurements on several silicon(Si)(111)
surfaces. Multitip-scanning tunneling microscopes are used
among others to determine the electrical conductance of
nanostructures. To get rid of the contact resistance, the
four-point method is used to measure the resistance of the
sample. Therefore four individual tips were used to make up
the multitip scanning tunneling microscope. Images of the
platin (Pt)(100) surface under ambient conditions show a
reconstructed surface, atomic steps and a drift of 1.6
Å/min after 18 hours. The development of a new
nanopositioner, the KoalaDrive, to approach the tip to the
sample, made the new multitip scanning tunneling microsope
ultra compact. However a setup of the KoalaDrive, which
works reliably in vacuum, had to be found. After a
successful characterization and further development of the
multitip scanning tunneling microscope, charge transport
measurements on several Si(111) surfaces were realised. The
conductance of the bismuthterminated Si(111)- $\sqrt{3}$ ×
$\sqrt{3}$ surface is comparable with a 3Å thick bismuth
layer. The conductivity of the bismuthterminated Si(111)-
$\sqrt{3}$ × $\sqrt{3}$ surface is (0.16 ± 0.07)
mS/$\Box$. The conductivity of the Si(111)-7×7 surface is
(4.0±0.1) μS/$\Box$ and therefore only 40 times smaller
than the conductivity of the bismuth- terminated silicon
surface. Additionally it will be shown that the Si(111)-7×7
surface is electrically strong decoupled from the bulk and
the main part of the current flows through the surface.
Furthermore the Si(111) surface will be hydrogen passivated
by using a chemical procedure. In doing this the surface
states were removed so that the bulk conductance of the
silicon sample could be measured. For a planned development
of a multitip scanning tunneling microscope in a multitip
atomic force microscopes the functionality of a
needle-sensor as a force detector will be varified. In
comparison to other sensors, the needle-sensor is very
compact and due to its geometry it would be optimal for
multitip atomic force microscopes. For positioning of all
four tips of the multitip atomic force microscope at one
location, the sensors have to be attached at an angle of
45$^{\circ}$ with respect to the surface. It becomes
apparent that the imaging of surfaces is more complicated
than using a sensor which is perpendicularly mounted to the
surface. ”Snap to contact” and eigenfrequencies of the
tip which are close to the eigenfrequency of the sensor
could be a possible explanation.},
keywords = {Dissertation (GND)},
cin = {PGI-3},
cid = {I:(DE-Juel1)PGI-3-20110106},
pnm = {142 - Controlling Spin-Based Phenomena (POF3-142)},
pid = {G:(DE-HGF)POF3-142},
typ = {PUB:(DE-HGF)3 / PUB:(DE-HGF)11},
url = {https://juser.fz-juelich.de/record/172749},
}