Droplet etching epitaxy for the nanostructuring of strain-free GaAs quantum dots
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Date
2024
Authors
Gossink, Declan Jotay
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Solomon, Glenn
Lewis, David
Lewis, David
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Thesis
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Abstract
Non-classical states of light in the form of single and entangled photons enable tests on fundamental physics and are the basis of many emerging quantum technologies. Since their inception, semiconductor quantum dots have been recognised as excellent sources of quantum light, and are considered to be one of the more promising sources for a scalable quantum architecture. To date, the highest performing quantum dots, in terms of multi-photon suppression, indistinguishability, and brightness, are realised by a process known as droplet etching epitaxy. The key result of the droplet etching technique is the formation of nanoholes on an epitaxial semiconductor film, which may then be subsequently filled in with a semiconductor of lower band-gap to create quantum dots. Invariably, the characteristics of the final quantum dots are dependent on the nanohole geometry. This thesis describes the experimental realisation of nanoholes of varying geometry using aluminium as etchant material on an AlGaAs epitaxial film. Using molecular beam epitaxy, the effects of substrate temperature, arsenic background pressure and droplet deposition flux on nanohole geometry are systematically studied. The nanoholes are then regrown with GaAs and capped with AlGaAs to create unstrained quantum dots. Light emission from as-created single and ensemble quantum dots are investigated. This work demonstrates the ability of droplet etching for structurally engineering low density quantum dots with emission properties desirable for quantum optic and nanophotonic experimentation.
School/Discipline
School of Physics, Chemistry and Earth Sciences : Physics
Dissertation Note
Thesis (MPhil.) -- University of Adelaide, School of Physics, Chemistry and Earth Sciences : Physics, 2024
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This thesis is currently under embargo and not available.