Indirect and direct optical transitions in In0.5Ga0.5As/GaP quantum dots

Stracke, Gernot; Sala, Elisa Maddalena; Selve, Sören; Niermann, Tore; Schliwa, A.; Strittmatter, A.; Bimberg, D.

doi:10.1063/1.4870087

Cited by 18 publications

(23 citation statements)

References 22 publications

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“…A significant improvement of the PL intensity was recently observed by playing with the QDs morphology and strain relief during the growth. It was attributed to the promotion of the direct bandgap transition, in good agreement with the previous theoretical description of the QDs electronic structure [34]. Still, the previous electronic structure modeling is not satisfactory in such a complex system, especially in the low In content range.…”

Section: Introductionsupporting

confidence: 71%

Electronic wave functions and optical transitions in (In,Ga)As/GaP quantum dots

et al. 2016

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Document VersionPublisher's PDF, also known as Version of Record (includes final page, issue and volume numbers) Please check the document version of this publication:• A submitted manuscript is the author's 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 publicationCitation for published version (APA): Robert, C., Pereira Da Silva, K., Nestoklon, M. O., Alonso, M. I., Turban, P., Jancu, J-M., ... Cornet, C. (2016). Electronic wave functions and optical transitions in (In,Ga)As/GaP quantum dots. Physical Review B, 94(7), 1-11. [075445]. DOI: 10.1103/PhysRevB.94.075445 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 ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. We study the complex electronic band structure of low In content InGaAs/GaP quantum dots. A supercell extended-basis tight-binding model is used to simulate the electronic and the optical properties of a pure GaAs/GaP quantum dot modeled at the atomic level. Transitions between hole states confined into the dots and several X Z -like electronic states confined by the strain field in the GaP barrier are found to play the main role on the optical properties. Especially, the calculated radiative lifetime for such indirect transitions is in good agreement with the photoluminescence decay time measured in time-resolved photoluminescence in the µs range. Photoluminescence experiments under hydrostatic pressure are also presented. The redshift of the photoluminescence spectrum with pressure is also in good agreement with the nature of the electronic confined states simulated with the tight-binding model.

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Section: Introductionsupporting

confidence: 71%

Electronic wave functions and optical transitions in (In,Ga)As/GaP quantum dots

et al. 2016

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“…However, the growth of defect-free systems, in particular by the most important mass production process MOCVD (Metal Organic Chemical Vapour Deposition), is very challenging due to the large lattice mismatch between Sb-and P-based structures (GaAs/GaP 3.6 %, In 0.5 Ga 0.5 As/GaP 7.4 %, InAs/GaP 11.5 %, GaSb/GaP 11.8 %, InSb/GaP 18.9 % [51]). Using specific growth engineering of MOCVD, In 0.5 Ga 0.5 As/GaP QDs have been obtained by Stracke et al [52,53] and a hole storage time at room temperature of about 4 min was reported [54]. Further improvement in the storage time beyond the magic 10 y limit might be obtained for type-II antimonybased QDs in an (AlGa)P matrix [55,56].…”

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confidence: 99%

Optical response of (InGa)(AsSb)/GaAs quantum dots embedded in a GaP matrix

et al. 2019

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The optical response of (InGa)(AsSb)/GaAs quantum dots (QDs) grown on GaP (001) substrates is studied by means of excitation and temperature-dependent photoluminescence (PL), and it is related to their complex electronic structure. Such QDs exhibit concurrently direct and indirect transitions, which allows the swapping of Γ and L quantum confined states in energy, depending on details of their stoichiometry. Based on realistic data on QD structure and composition, derived from high-resolution transmission electron microscopy (HRTEM) measurements, simulations by means of k · p theory are performed. The theoretical prediction of both momentum direct and indirect type-I optical transitions are confirmed by the experiments presented here. Additional investigations by a combination of Raman and photoreflectance spectroscopy show modifications of the hydrostatic strain in the QD layer, depending on the sequential addition of QDs and capping layer. A variation of the excitation density across four orders of magnitude reveals a 50 meV energy blueshift of the QD emission. Our findings suggest that the assignment of the type of transition, based solely by the observation of a blueshift with increased pumping, is insufficient. We propose therefore a more consistent approach based on the analysis of the character of the blueshift evolution with optical pumping, which employs a numerical model based on a semi-self-consistent configuration interaction method.

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“…Most of the investigations conducted in this field have focused on only one of energy level change by indium content or lasing process, and they have not investigated the direct effect of stoichiometric percentage on lasing, and hardly a paper can be seen studying the stoichiometry effect in laser applications. Indium percentages of 0.4 and 0.5 have been used in laser devices [25][26][27]. Strain leads to formation of different size of QDs.…”

Section: Introductionmentioning

confidence: 99%

Influence of Indium-Percentage Variation on Dynamical Characteristics of InxGa1-xAs/GaAs(001) Quantum Dot Lasers

Borji

Rajaei

2016

Iran J Sci Technol Trans Sci

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The influence of indium percentage on dynamical characteristics of InxGa1-xAs/GaAs(001) quantum dot lasers (QDLs) is investigated. Energy levels of self-organized truncated-cone-shape QDs are calculated by means of the eight-band k.p model, and their dependence to indium percentage is surveyed. Then, by presenting a three-level model and numerical solution of the resulting rate equations, laser properties are determined. Our results show that inclusion of more indium gives rise in the reduced energy gap and electron-hole recombination energy. Moreover, lasing process for both Ground State (GS) and Excited States (ES) sound to be sensitive to indium percentage. It is shown that rise of indium percentage at fixed injected current results in the increased ES turn-on delay and GS photon number and 3dB modulation bandwidth, and decreased ES photon number, GS turn on delay, amplitude of relaxation oscillations, output power, and ES 3dB modulation bandwidth; but has no effect on threshold current and laser gain. At last, we find an optimized cavity length which was likely to be independent of indium percentage.

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Indirect and direct optical transitions in In0.5Ga0.5As/GaP quantum dots

Cited by 18 publications

References 22 publications

Electronic wave functions and optical transitions in (In,Ga)As/GaP quantum dots

Electronic wave functions and optical transitions in (In,Ga)As/GaP quantum dots

Optical response of (InGa)(AsSb)/GaAs quantum dots embedded in a GaP matrix

Influence of Indium-Percentage Variation on Dynamical Characteristics of InxGa1-xAs/GaAs(001) Quantum Dot Lasers

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