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Lookup NU author(s): Dr Jonathan Mar
This is the final published version of an article that has been published in its final definitive form by American Physical Society, 2011.
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We present bias-dependent micro-photoluminescence (μ-PL) spectroscopy of the neutral (X0) and singly negatively-charged (X−) excitons in single InAs/GaAs self-assembled quantum dots (QDs) embedded in the intrinsic region of an n-i-Schottky diode based on a two-dimensional electron gas (2DEG), which was obtained from a Si δ-doped GaAs layer. Using such a device structure, we demonstrate bias-controlled single-electron charging of a single QD as the QD s-shell electron state is tuned below the Fermi level. This is verified experimentally by the sequential appearance of energetically-distinct PL emission lines from the two excitons and supported by theoretical calculations. In addition, it is shown both experimentally and theoretically that simultaneous PL emission from the X0 and X− excitons within a particular bias range is the result of a long-lived charge-nonequilibrium state due to weak tunnel-coupling between the QDs and 2DEG in our device. Further, the ability to tune the exciton transition energies via the quantum-confined Stark effect is observed, offering insight into the carrier wave function distributions in the QD and the QD material structure. Finally, we propose a number of spintronic device concepts that may be made feasible as a result of this investigation into bias-controlled carrier tunneling between a self-assembled QD and a 2DEG.
Author(s): Mar JD, Xu XL, Baumberg JJ, Brossard FSF, Irvine AC, Stanley C, Williams DA
Publication type: Article
Publication status: Published
Journal: Physical Review B (Editors' Suggestion)
Year: 2011
Volume: 83
Online publication date: 14/02/2011
Date deposited: 15/06/2020
ISSN (print): 2469-9950
ISSN (electronic): 2469-9969
Publisher: American Physical Society
URL: https://doi.org/10.1103/PhysRevB.83.075306
DOI: 10.1103/PhysRevB.83.075306
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