Optical investigations of the dynamic behavior of GaSb/GaAs quantum dots

Sun, Chi‐Kuang; Wang, G.; Bowers, John E.; Brar, B.; Blank, H.-R.; Kroemer, H.; Pilkuhn, M. H.

doi:10.1063/1.115693

Cited by 166 publications

(115 citation statements)

References 11 publications

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“…A number of PL measurements have been published on GaSb dots made both in this laboratory 7 and others, 6,8 and they have associated a PL line at 1.14 eV with the recombination of an electron in the GaAs with a hole in the GaSb. This PL data is consistent with the DLTS reported here.…”

Section: Discussionmentioning

confidence: 99%

“…Photoluminescence ͑PL͒ experiments have demonstrated that GaSb QDs are significantly different from In x Ga 1Ϫx As/GaAs QDs are they have a type II band structure with a well in the GaSb valence band, which captures holes, and a barrier in the conduction band, which prevents the capture of electrons. [6][7][8] This band structure may be useful in electronic devices, particularly those requiring charge storage.…”

Section: Introductionmentioning

confidence: 99%

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Deep level transient capacitance measurements of GaSb self-assembled quantum dots

Magno¹,

Bennett²,

Glaser³

2000

Journal of Applied Physics

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Deep level transient spectroscopy ͑DLTS͒ measurements have been made on GaAs n ϩ p diodes containing GaSb self-assembled quantum dots and control junctions without dots. The self-assembled dots were formed by molecular beam epitaxy using the Stranski-Krastanov growth mode. The dots are located in the depletion region on the p side of the junction where they act as a potential well that may capture and emit holes. Spectra recorded for temperatures between 77 and 440 K reveal several peaks in diodes containing dots. A control sample with a GaSb wetting layer was found to contain a single broad high temperature peak that is similar to a line found in the GaSb quantum dot samples. No lines were found in the spectra of a control sample prepared without GaSb. DLTS profiling procedures indicate that one of the peaks is due to a quantum-confined energy level associated with the GaSb dots while the others are due to defects in the GaAs around the dots. The peak identified as a quantum-confined energy level shifts to higher temperatures and its intensity decreases on increasing the reverse bias. The activation energy for the quantum-confined level increases from 400 meV when measured at a low reverse bias to 550 meV for a large reverse bias. Lines with activation energies of 400, 640, and 840 meV are associated with defects in the GaAs based on the bias dependence of their peak positions and amplitudes.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Deep level transient capacitance measurements of GaSb self-assembled quantum dots

Magno¹,

Bennett²,

Glaser³

2000

Journal of Applied Physics

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“…The spatial separation of electrons and holes in type-II structures results in long exciton lifetimes, [2][3][4] resulting in interesting applications for longwavelength optoelectronics. 5 The exclusive confinement of holes and their large localization energy makes GaSb/GaAs QDs particularly interesting for charge storage devices.…”

Section: Introductionmentioning

confidence: 99%

“…5 The exclusive confinement of holes and their large localization energy makes GaSb/GaAs QDs particularly interesting for charge storage devices. [6][7][8] GaSb/GaAs QDs were first grown using molecular beam epitaxy 2,9 and later by metal-organic chemical vapor epitaxy, 10,11 followed by optical characterization, 9,[12][13][14][15] cross-section scanning electron microscopy investigations, 16 and deep-level transient spectroscopy (DLTS) studies, 17,18 accompanied by numerical calculations. [19][20][21] The various investigations have been performed on different samples.…”

Section: Introductionmentioning

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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“…19 The type-II blueshift was quantified in the fine structure of the rings' emission using two techniques: (i) applying a Lorentzian fit to individual exciton peaks and extracting the central position, and (ii) following a centre-of-mass (CoM) fitting procedure by integrating each µPL spectrum and calculating the point corresponding to the pixel value in which the half-area falls. The results of these two techniques are illustrated on top of the experimental data shown in Fig.…”

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confidence: 99%

Photoluminescence studies of individual and few GaSb/GaAs quantum rings

et al. 2014

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We present optical studies of individual and few GaSb quantum rings embedded in a GaAs matrix. Contrary to expectation for type-II confinement, we measure rich spectra containing sharp lines. These lines originate from excitonic recombination and are observed to have resolution-limited full-width at half maximum of 200 μeV. The detail provided by these measurements allows the characteristic type-II blueshift, observed with increasing excitation power, to be studied at the level of individual nanostructures. These findings are in agreement with hole-charging being the origin of the observed blueshift.

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Optical investigations of the dynamic behavior of GaSb/GaAs quantum dots

Cited by 166 publications

References 11 publications

Deep level transient capacitance measurements of GaSb self-assembled quantum dots

Deep level transient capacitance measurements of GaSb self-assembled quantum dots

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

Photoluminescence studies of individual and few GaSb/GaAs quantum rings

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