h1

TY  - THES
AU  - Rieger, Torsten
TI  - Growth and structural characterization of III-V semiconductor nanowires
PB  - RWTH Aachen
VL  - Dissertation
CY  - Aachen
M1  - RWTH-2015-07321
SP  - 1 Online-Ressource (getrennte Zählung) : Illustrationen, Diagramme
PY  - 2015
N1  - Veröffentlicht auf dem Publikationsserver der RWTH Aachen University 2016
N1  - Dissertation, RWTH Aachen, 2015
AB  - In this thesis, the growth and structural properties of III-V semiconductor nanowires and nanowire heterostructures are studied. These nanowires represent structures suitable for both fundamental physics and applications in electronic devices such as (tunnel) field effect transistors. The III-V nanowires are grown with molecular beam epitaxy, high κ dielectric layers are deposited conformally around the nanowires by atomic layer deposition. The morphological and structural characteristics of the obtained structures are analyzed by scanning and transmission electron microscopy as well as x-ray diffraction.InAs nanowires are grown via two different growth mechanisms on both GaAs and Si (111) substrates. The growth proceeds either in the vapor-liquid-solid mechanism involving a liquid In droplet or via the vapor-solid growth mechanism without the use of any catalyst particle. A thorough analyzes of the impact of the substrate preparation on the nanowire growth is conducted and optimal parameters for the in situ and ex situ substrate preparations are identified. The vapor-solid grown InAs NWs exhibit a high density of stacking defects while the growth via the vapor-liquid-solid mechanism results in zinc blende twinning super lattices with a short wurtzite segment below the catalyzing In droplet. This wurtzite segment is attributed to a nucleation at the triple phase line between the vapor, the liquid droplet and the solid crystal. After developing a kinetic model for the presence of the wurtzite phase below the droplet, it becomes possible to include wurtzite segment of various lengths in GaAs and InAs nanowires grown via the vapor-liquid-solid mechanism.The growth of InAs and GaAs nanowires is successfully transferred to Si (100) substrates applying a texturing process to the Si substrate. This produces pyramids bound by 111 facets. An alignment of the pyramids with respect to the effusion cells allows us to control the nanowire growth direction and to study the impact of the growth parameters within a single growth experiment. Furthermore, the textured substrates enable a simultaneous integration of GaAs and InAs nanowires on the very same sample.Nanowire heterostructures are investigated by means of almost lattice matched combinations (InAs, GaSb and AlSb) as well as highly lattice mismatched heterostructures (GaAs/InAs and GaAs/InSb). The latter exhibit a lattice mismatch of 7
LB  - PUB:(DE-HGF)11
UR  - https://publications.rwth-aachen.de/record/564332
ER  -