Quantum Transport Characterizations in Selective-Area Grown InGaAs Nanowire Networks

Cerveny, Kristopher. Quantum Transport Characterizations in Selective-Area Grown InGaAs Nanowire Networks. 2022, Doctoral Thesis, University of Basel, Faculty of Science.


Official URL: https://edoc.unibas.ch/90311/

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Selective-area-grown (also referred to as ‘templated’) semiconductor nanostructures have gen-
erated considerable research interest in recent years as potential vehicles for the investigation of
fundamental quantum phenomena as well as towards scalable networks for deployment in future
quantum computers. Such structures made from III-V semiconductors, which can play host to
effects such as strong spin-orbit interaction and Fermi-level pinning of the conduction band at
the interface, are of interest due to the fast spin precession as well as being potential vehicles for
realization of non-trivial topological states of matter.
This nascent technology has relied on the bridging of growth techniques, nano-fabrication,
low-temperature electronic transport studies, and compositional analysis during its development.
The required expertise involved has resulted in fruitful collaborations between a number of re-
search groups in different institutions, which has enabled steady progress. Devices have been
fabricated on quasi-1D nanostructures comprised of InGaAs nanowires grown atop defect-free
GaAs nanomembranes, first with bulk-doping of Si + donors in the InGaAs wires in order to
demonstrate a proof-of-principle for the system.
Later, devices utilizing modulation doping strategies in order to reduce impurity scattering -
while still providing the necessary additional carriers for transport - have been realized, measured,
and analysed. Devices with branched geometries have been produced and quantum intereference
effects have been observed across the junctions. Important transport parameters such as mean
free paths, coherence lengths and spin-orbit lengths have been extracted in order to characterize
the structures and motivate the next steps along the evolution of the systems. Novel fabrication
techniques have been developed and employed in order to investigate and control various aspects
of the structures, including carrier density and electric fields across the wires.
Advisors:Zumbühl, Dominik M and Klinovaja, Jelena and Schäpers, Thomas
UniBasel Contributors:Klinovaja, Jelena
Item Type:Thesis
Thesis Subtype:Doctoral Thesis
Thesis no:14861
Thesis status:Complete
Number of Pages:155
Identification Number:
  • urn: urn:nbn:ch:bel-bau-diss148619
edoc DOI:
Last Modified:10 Dec 2022 05:30
Deposited On:09 Dec 2022 15:57

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