Control of complex quantum structures in droplet epitaxy

Chawner, J M A and Chang, Y and Hodgson, P D and Hayne, M and Robson, A J and Sanchez, A M and Zhuang, Q (2019) Control of complex quantum structures in droplet epitaxy. Semiconductor Science and Technology, 34 (9): 095011. ISSN 0268-1242

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We report the controllable growth of GaAs quantum complexes in droplet molecular-beam epitaxy, and the optical properties of self-assembled AlxGa1-xAs quantum rings embedded in a superlattice. We found that Ga droplets on a GaAs substrate can retain their geometry up to a maximum temperature of 490 degrees C during post-growth annealing, with an optimal temperature of 320 degrees C for creating uniform and symmetric droplets. Through controlling only the crystallisation temperature under As-4 in the range of 450 degrees C to 580 degrees C, we can reliably control diffusion, adsorption and etching rates to produce various GaAs quantum complexes such as quantum dots, dot pairs and nanoholes. AlxGa1-xAs quantum rings are also realised within these temperatures via the adjustment of As beam equivalent pressure. We found that crystallisation using As-2 molecules in the place of As-4 creates smaller diameter quantum rings at higher density. The photoluminescence of As-2 grown AlxGa1-xAs quantum rings embedded in a superlattice shows a dominant emission from the quantum rings at elevated temperatures. This observation reveals the properties of the quantum ring carrier confinement and their potential application as efficient photon emitters.

Item Type:
Journal Article
Journal or Publication Title:
Semiconductor Science and Technology
Additional Information:
This is an author-created, un-copyedited version of an article accepted for publication/published in Semiconductor Science and Technology. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at doi:10.1088/1361-6641/ab337e
Uncontrolled Keywords:
?? droplet epitaxymolecular beam epitaxyquantum structurephotoluminescenceatomic force microscopytransmission electron microscopymaterials chemistryelectronic, optical and magnetic materialselectrical and electronic engineeringcondensed matter physics ??
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Deposited On:
04 Oct 2019 10:30
Last Modified:
05 Jan 2024 00:24