from 28 June 2015 to 3 July 2015 (Africa/Johannesburg)
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SAIP2015 Proceeding published on 17 July 2016
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MOCVD growth of GaSb/GaAs quantum dots

Presented by Mr. Ngcali TILE on 30 Jun 2015 from 16:10 to 18:00
Type: Poster Presentation
Session: Poster1
Track: Track A - Division for Physics of Condensed Matter and Materials
Board #: A.180


Quantum dots (QDs) formed through the creation of Gallium Antimonide (GaSb) nanostructures in a Gallium Arsenide (GaAs) matrix have some unique and appealing properties that are being continually exploited. This system has a type-II band alignment, providing strong spatial confinement for holes, and only binding electrons via the Coulomb interaction, leading to optical properties different from type-I QDs, such as a long radiative lifetime, a dot-shape dependent oscillator strength, and a large tunability of emitted/absorbed photons. It has been found recently that GaAs based p-i-n solar cells containing layers of GaSb quantum dots/rings fabricated by Molecular Beam Epitaxy showed improved efficiency at longer wavelengths of up to 1.5 μm. In order to improve this device functionality there is a need to understand the formation of these dot structures in order to control/tune their structural properties and therefore improve their optical and electrical properties. A Metal Organic Chemical Vapor Deposition (MOCVD) system provides a set of deposition conditions that would allow one to systematically study the QD formation. In this work we show the fabrication of GaSb QDs in a GaAs matrix using MOCVD. Tributylarsenic, Triethygallium (TEGa), and Trisdimethyaminoantimony (TDMASb) were used as arsenic, gallium, and antimony sources, respectively. We studied the influence of TDMASb/TEGa ratio and growth temperature on the size, morphology and density of the QD structures. We also studied the optical properties of the capped QD structures by photoluminescence spectroscopy.






J.R Botha (NMMU),