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@MASTERSTHESIS{Nagda:862659,
author = {Nagda, Gunjan},
othercontributors = {Lepsa, Mihail Ion},
title = {{MBE} growth and characterization of {I}n{A}s/{G}a{S}b
core/shell nanowire arrays},
school = {RWTH Aachen},
type = {Masterarbeit},
address = {Jülich},
publisher = {Forschungszentrum Jülich},
reportid = {FZJ-2019-02915,},
pages = {101},
year = {2019},
note = {Masterarbeit, RWTH Aachen, 2019},
abstract = {III-V semiconductor compounds InAs and GaSb are almost
lattice matched and when incontact, the heterostructure
appears to have a broken gap alignment at their
interface[1].In a core/shell nanowire (NW) geometry, these
particularities make this combination interestingfor low
power electronic devices (Tunneling Field Effect
Transistors) as well as thestudy of fundamental physical
properties such as quantum effects arising due to
electroninterference. This thesis reports on the MBE growth
as well as the structural and electricalcharacterization of
InAs/GaSb NW arrays.For the growth, a Si(111) substrate is
covered with a thin thermal SiO2 film in
whichtwo-dimensional, periodic arrays of nano-sized holes
are patterned. The InAs NW growth isoptimized regarding the
yield and morphology of the wires. Substrate preparation
therebyis crucial for achieving a high NW yield. The
subsequent growth of the GaSb shell hasbeen investigated and
optimum growth conditions have been achieved. The effect of
dopingof the GaSb shell and substrate temperature, during
shell deposition, is also studied.NW morphology and
structural characteristics have been investigated. The small
latticemismatch between InAs and GaSb combined with the
one-dimensional geometry result in amisfit dislocation free
coreshell NW hetero-interface.Post-growth, the GaSb shell is
etched from part of the NW to have access to the InAscore in
order to study the transport at the hetero-junction. Dry and
wet etching techniquesprovide different results, both of
which can be used for fabricating NW devices.
Metalliccontacts have been fabricated on different parts of
these partially etched core/shell NWs aswell as on
non-etched wires. This process is optimized for the
dimensions of these core/shellNWs with respect to
reproducibility.Electrical characterization includes gate
dependent measurements, which have been carriedout at room
temperature as well as at low temperatures down to 1.5K
using a cryogenicsetup. Magneto-transport measurements are
used to probe electron transport in thesenanoscopic systems.
Characterization therefore includes the observation of
quantum mechanicalelectron interference effects probed at
different temperatures and different anglesof the magnetic
field with respect to the NW axis. Analysis on this data
includes approximationsof typical figures of merit like the
phase coherence length or the elastic mean freepath but also
includes a proper analysis of the size and possible
locations of the electroninterference loops.},
cin = {PGI-9 / PGI-10 / JARA-FIT},
cid = {I:(DE-Juel1)PGI-9-20110106 / I:(DE-Juel1)PGI-10-20170113 /
$I:(DE-82)080009_20140620$},
pnm = {521 - Controlling Electron Charge-Based Phenomena
(POF3-521)},
pid = {G:(DE-HGF)POF3-521},
typ = {PUB:(DE-HGF)29 / PUB:(DE-HGF)19},
url = {https://juser.fz-juelich.de/record/862659},
}