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@PHDTHESIS{Wirtssohn:775258,
author = {Wirtssohn, Matti},
othercontributors = {Wuttig, Matthias and Waser, Rainer},
title = {{S}tudy on growth of epitaxial single domain tin-telluride
and epitaxial antimony on silicon and sputter-grown
bismuth-tin-telluride nanowhiskers},
school = {RWTH Aachen University},
type = {Dissertation},
address = {Aachen},
reportid = {RWTH-2019-12085},
pages = {1 Online-Ressource (ix, 171, XLIII Seiten) :
Illustrationen, Diagramme},
year = {2019},
note = {Veröffentlicht auf dem Publikationsserver der RWTH Aachen
University 2020; Dissertation, RWTH Aachen University, 2019},
abstract = {This work mainly deals with the deposition and
characterization of thin films on silicon surfaces. Within
this work, three different material systems are studied.
Consequently it is divided into the following three
sections:1. Epitaxial growth of SnTe(001) on Si(111)2.
Epitaxial growth of Sb(0001) on Si(111)3. Sputter-grown
bismuth-tin-telluride nanowhiskers. The first two segments
focus on investigation and discussion of the growth process
and resulting structure of the given materials. The third
chapter however, is centered more on the handling and
preparation of sputtered crystalline nanostructures to test
their feasibility for further device fabrication. The growth
process of epitaxial SnTe(001) on
Si(111)−$\sqrt3$×$\sqrt3$−R30°−Sb terminated
surfaces is studied. From the combination of the threefold
symmetry of the Si(111) surface and the fourfold symmetry of
the cubic SnTe(001) layer, a twelve-fold symmetry of three
energetically equivalent rotational domains should
expectably emerge. The presented films however, are
single-domain SnTe(001) films. It will be shown, that by
alignment of the wafer miscut and the Sb surface
termination, the rotational symmetry of the film-substrate
interface can be eliminated. As a result the SnTe(001)
layers are governed by only one rotational domain. These
findings are compared to SnTe(001) films grown on Si(111)
− 7 × 7 reconstructed surfaces, consisting of six
rotational domains. This illustrates the vast improvements
made possible by the presented growth process. This
mechanism of breaking the symmetry condition at the
film-substrate interface might likewise apply similarly to
other systems. Furthermore the gathered information on SnTe
growth behavior is exploited to fabricate single-domain
SnTe(001) devices for electrical testing. Electrical testing
is carried out at temperatures between 2 K and 300 K. The
devices consist of SnTe layers with a Sn contents of 50.0
at.\% to 51.5 at.\%. The growth of epitaxial Sb on the
Si(111) − 7 × 7 surface reconstruction is presented.
Highly out-of-plane textured Sb(0001) layers were produced
by molecular beam epitaxy. Substrate temperature, deposition
rate and film thickness are varied and compared. In all
scenarios the film consists of predominantly smooth and flat
Sb(0001) and some Sb(01$\bar1$2) grains. The observations
suggests that at first the step edges and Si(111) − 7 × 7
domain boundaries on the surface are decorated with
approximately 2 nm Sb. Then the film starts growing from
these decorated steps as crystalline Sb(0001) islands. The
Sb(01$\bar1$2) grains are found to emerge on these
steps/domain boundaries as well. The Sb(0001) films exhibit
rotational domains of ±6.1°, ±16.0° and ±30.1°
regarding the silicon substrate. The results are compared to
GeTe and Sb$_{2}$Te$_{3}$ films grown under comparable
conditions. Sputter-grown Sn$_{x}$Bi$_{y}$Te$_{z}$
nanowhiskers are presented. Structural analysis determines
highly ordered nanowhiskers free of structural defects.
Analysis of the composition yields a
Sn$_{1}$Bi$_{2}$Te$_{4}$ stoichiometry. The presented
handling of the nanostructures shows that further processing
can be done to fabricate functional devices. Conducted
4-terminal-sensing is performed as a proof of concept,
showing that other methods of characterization are possible
on the devices.},
cin = {131110 / 130000},
ddc = {530},
cid = {$I:(DE-82)131110_20140620$ / $I:(DE-82)130000_20140620$},
typ = {PUB:(DE-HGF)11},
doi = {10.18154/RWTH-2019-12085},
url = {https://publications.rwth-aachen.de/record/775258},
}
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