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Voltage-controlled electron tunneling from a single self-assembled quantum dot embedded in a two-dimensional-electron-gas-based photovoltaic cell

Lookup NU author(s): Dr Jonathan Mar

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This is the final published version of an article that has been published in its final definitive form by AIP Publishing LLC, 2011.

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Abstract

We perform high-resolution photocurrent (PC) spectroscopy to investigate resonantly the neutral exciton ground-state (X⁰) in a single InAs/GaAs self-assembled quantum dot (QD) embedded in the intrinsic region of an n-i-Schottky photodiode based on a two-dimensional electron gas (2DEG), which was formed from a Si δ-doped GaAs layer. Using such a device, a single-QD PC spectrum of X⁰ is measured by sweeping the bias-dependent X⁰ transition energy through that of a fixed narrow-bandwidth laser via the quantum-confined Stark effect (QCSE). By repeating such a measurement for a series of laser energies, a precise relationship between the X⁰ transition energy and bias voltage is then obtained. Taking into account power broadening of the X⁰ absorption peak, this allows for high-resolution measurements of the X⁰ homogeneous linewidth and, hence, the electron tunneling rate. The electron tunneling rate is measured as a function of the vertical electric field and described accurately by a theoretical model, yielding information about the electron confinement energy and QD height. We demonstrate that our devices can operate as 2DEG-based QD photovoltaic cells and conclude by proposing two optical spintronic devices that are now feasible.

Publication metadata

Author(s): Mar JD, Xu XL, Baumberg JJ, Irvine AC, Stanley C, Williams DA

Publication type: Article

Publication status: Published

Journal: Journal of Applied Physics

Year: 2011

Volume: 110

Issue: 5

Online publication date: 15/09/2011

Date deposited: 15/06/2020

ISSN (print): 0003-6951

ISSN (electronic): 1077-3118

Publisher: AIP Publishing LLC

URL: https://doi.org/10.1063/1.3633216

DOI: 10.1063/1.3633216

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