Hole and electron emission from InAs quantum dots

Kapteyn, C. M. A.; Lion, M.; Heitz, R.; Bimberg, D.; Brunkov, P. N.; Volovik, B. V.; Konnikov, S. G.; Kovsh, A. R.; Ustinov, V. M.

doi:10.1063/1.126099

Cited by 110 publications

(71 citation statements)

References 14 publications

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“…C-V measurements and in particular DLTS measurements [27][28][29] are the best methods to obtain detailed information about their position. Previously, there have been only two DLTS studies of the GaSb/GaAs QD system to the best of our knowledge.…”

Section: Electrical Investigationmentioning

confidence: 99%

Linking structural and electronic properties of high-purity self-assembled GaSb/GaAs quantum dots

et al. 2012

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Hayne, M. (2012). Linking structural and electronic properties of high-purity self-assembled GaSb/GaAs quantum dots. Physical Review B, 86(3) Please check the document version of this publication:• A submitted manuscript is the version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal.If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the "Taverne" license above, please follow below link for the End User Agreement: www.tue.nl/taverne Take down policyIf you believe that this document breaches copyright please contact us at: openaccess@tue.nl providing details and we will investigate your claim. We present structural, electrical, and theoretical investigations of self-assembled type-II GaSb/GaAs quantum dots (QDs) grown by molecular beam epitaxy. Using cross-sectional scanning tunneling microscopy (X-STM) the morphology of the QDs is determined. The QDs are of high purity (∼100% GaSb content) and have most likely the shape of a truncated pyramid. The average heights of the QDs are 4-6 nm with average base lengths between 9 and 14 nm. Samples with a QD layer embedded into a pn-diode structure are studied with deep-level transient spectroscopy (DLTS), yielding a hole localization energy in the QDs of 609 meV. Based on the X-STM results the electronic structure of the QDs is calculated using 8-band k·p theory. The theoretical localization energies are found to be in good agreement with the DLTS results. Our results also allow us to estimate how variations in size and shape of the dots influence the hole localization energy.

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Section: Electrical Investigationmentioning

confidence: 99%

Linking structural and electronic properties of high-purity self-assembled GaSb/GaAs quantum dots

et al. 2012

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“…The QD ground state localization energy obtained here from admittance spectroscopy, is at least twice as high as, e.g., for structurally comparable InAs/GaAs QDs [5,9]. In order to compare the influence on the storage time constants, we calculate the emission rates for GaSb/GaAs and InAs/GaAs QDs at 300 K with help of Eq.…”

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confidence: 99%

“…In order to investigate the electronic properties and the carrier dynamics in QD systems, capacitance spectroscopy has been demonstrated to be a feasible tool [5]. Previously, we have employed deep level transient spectroscopy (DLTS) [6] and admittance spectroscopy to study InAs/GaAs [7][8][9] and Ge/Si QDs [10]. QD formation in the latter material system, however, typically leads to rather large islands and low area densities, which renders it considerably less attractive.…”

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Hole storage in GaSb/GaAs quantum dots for memory devices

Geller¹,

Kapteyn

Müller‐Kirsch

et al. 2003

Physica Status Solidi (b)

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The hole confinement of self-organized GaSb/GaAs quantum dots embedded in n + p-diodes is investigated experimentally by admittance spectroscopy. The highest thermal activation energy obtained, 400 meV, refers to only weakly charged quantum dots. Detailed bias-dependent investigations allow to study state-filling and Coulomb charging effects. State filling lowers the activation energy down to 150 meV in quantum dots charged with the maximum number of about 15 holes. The observed thermal activation barrier for GaSb/GaAs quantum dots is about twice as high as for structurally comparable InAs/GaAs quantum dots.The ultimate non-volatile electronic memory cell confines a single carrier to represent a bit of information [1]. As conventional material processing technology is not yet able to manufacture suitable semiconductor structures, self-organized quantum dots (QDs) offer an elegant method to create huge ensembles of electronic traps for single or very few carriers [2]. So far, mainly the applicability of InAs/GaAs QDs for memory concepts has been studied, see e.g. Refs. [3,4]. A crucial parameter for memory operation is the thermal activation barrier for the trapped carriers -the larger it is, the longer the storage time becomes. In order to investigate the electronic properties and the carrier dynamics in QD systems, capacitance spectroscopy has been demonstrated to be a feasible tool [5]. Previously, we have employed deep level transient spectroscopy (DLTS) [6] and admittance spectroscopy to study InAs/GaAs [7][8][9] and Ge/Si QDs [10]. QD formation in the latter material system, however, typically leads to rather large islands and low area densities, which renders it considerably less attractive. InAs/GaAs QDs, on the other hand, typically exhibit electron and hole ground state localisation energies in the order of up to about 200 meV. GaSb/GaAs QDs have similar structural properties as typical InAs/GaAs QDs, but a significantly larger hole ground state localization energy is expected due to the type-II band alignment attractive for holes [11]. Here, we study the thermal activation barrier of hole-charged GaSb/GaAs QDs by admittance spectroscopy for varying filling conditions. The layer structure of the investigated GaSb QD sample, grown by metal organic chemical vapor deposition [12,13], is schematically depicted in Fig. 1a. A 500 nm thick highly p-doped contact layer (p = 1 × 10 18 cm -3 ) and a 700 nm thick p-doped GaAs layer (p = 3 × 10 16 cm -3) were deposited on top of a semi-insulating GaAs substrate. Subsequently, a layer of GaSb QDs (2.8 ML nominally) was created in the Stranski-Krastanow growth mode. The QD layer is sandwiched between two 10 nm thick undoped GaAs spacers, and followed by 500 nm p-doped GaAs (p = 3 × 10 16 cm -3 ). Finally, 400 nm of highly ndoped GaAs (n = 7 × 10 17 cm -3 ) was deposited in order to form a n + p diode structure. Employing standard optical lithography and chemical wet-etching, mesa structures with a diameter of 800 µm were created. Standard Ohmic contacts were formed on...

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“…PL intensity decay in InAs QDs as a rule attributed to thermal escape of carriers from QDs into the wetting layer or into the GaAs barrier [5][6][7][8], as well as to thermally activated capture of excitons by nonradiative defects in the GaAs barrier or at the GaAs/InAs interface [5,9,10]. The unusual variations of emission energy and the full width at half maximum (FWHM) of PL bands in the InAs/GaAs self-assembled QDs have been investigated earlier as well [11,12].…”

Section: Introductionmentioning

confidence: 99%

“…In these systems, the strong localization of an electronic wave function leads to an atomic-like electronic density of states and permits to realize the novel and improved photonic and electronic devices. Microlectronic and optoelectronic devices based on quantum wells (QWs) with InAs QDs have been the subject of investigation for the applications in semiconductor lasers for the optical fiber communication [1][2][3], infrared photo-detectors [4][5][6], electronic memory devices [7,8], as well as single electron devices and single photon light sources on the base of single-QD structures for the quantum information applications [9][10][11][12]. QDs are especially attractive for the applications in semiconductor lasers.…”

Section: Introductionmentioning

confidence: 99%

InAs Quantum Dots in Symmetric InGaAs/GaAs Quantum Wells

Torchynska¹

2012

Fingerprints in the Optical and Transport Properties of Quantum Dots

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Hole and electron emission from InAs quantum dots

Cited by 110 publications

References 14 publications

Linking structural and electronic properties of high-purity self-assembled GaSb/GaAs quantum dots

Linking structural and electronic properties of high-purity self-assembled GaSb/GaAs quantum dots

Hole storage in GaSb/GaAs quantum dots for memory devices

InAs Quantum Dots in Symmetric InGaAs/GaAs Quantum Wells

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