Achievement of High Density InAs Quantum Dots on InP (311)B Substrate Emitting at 1.55 µm

Caroff, Philippe; Bertru, Nicolas; Corre, Alain Le; Dehaese, Olivier; Rohel, Tony; Alghoraibi, Ibrahim; Folliot, Hervé; Loualiche, Slimane

doi:10.1143/jjap.44.l1069

Cited by 35 publications

(32 citation statements)

References 14 publications

(12 reference statements)

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“…13,14 This research is devoted to the study of the InAs/Q1.18 QD system on a ͑311͒B InP substrate, where Q1.18 is the quaternary alloy In 0.8 Ga 0.2 As 0.435 P 0.565 , emitting at a wavelength of 1.18 m at room temperature. By decreasing the As flux, and with the same amount of InAs deposited, the QDD can increase as high as 1.6ϫ 10 11 cm −2 .…”

Section: Growth Of Quantum Dots Superlatticesmentioning

confidence: 99%

Increase of charge-carrier redistribution efficiency in a laterally organized superlattice of coupled quantum dots

et al. 2006

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We report the observation of enhanced charge-carrier redistribution in laterally organized and coupled InAs/ InP quantum dots ͑QDs͒. We show that a periodic organization appears in the QD plane for a high in-plane QD density ͑QDD͒. This organization enhances the lateral coupling between the dots, which is evidenced by photoluminescence and magnetophotoluminescence experiments. Electronic inter-QD lateral coupling results in an improved charge-carrier distribution at low temperature, as shown by electroluminescence on high QDD QD lasers. We conclude that the inter-QD tunneling occurs via the tunneling of excited states through the wetting layer, and discuss the prospects of using coupled QDs for improving the quantum efficiency and dynamical properties of QD lasers.

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Section: Growth Of Quantum Dots Superlatticesmentioning

confidence: 99%

Increase of charge-carrier redistribution efficiency in a laterally organized superlattice of coupled quantum dots

et al. 2006

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“…1,2 In comparison with InAs dot formation on conventional ͑100͒ InP substrates, a higher density of dots, having a smaller size dispersion, has been achieved by deposition of InAs layers on high index ͑311͒B InP substrates. 3,4 Indeed, room temperature lasers with low threshold current density emitting at 1.5 m were recently demonstrated. 5 Despite this progress, the effect of the capping material on the structural properties of the QDs is still under investigation.…”

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confidence: 99%

Capping of InAs quantum dots grown on (311)B InP studied by cross-sectional scanning tunneling microscopy

Çelebi

Ulloa

Koenraad

et al. 2006

Applied Physics Letters

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Cross-sectional scanning tunneling microscopy was used to study at the atomic scale the impact of the capping material on the structural properties of self-assembled InAs quantum dots (QDs) grown on a high index (311)B InP substrate. Important differences were found in the capping process when InP or lattice matched InGaAs(P) alloys are used. The QDs capped with InP have a smaller height due to As∕P exchange induced decomposition. This effect is not present when InGaAs is used as the capping material. However, in this case a strong strain driven phase separation appears, creating In rich regions above the QDs and degrading the dot/capping layer interface. If the InAs dots are capped by the quaternary alloy InGaAsP the phase separation is much weaker as compared to capping with InGaAs and well defined interfaces are obtained.

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“…Nevertheless, different materials such as InGaAs and GaAsSb are nowadays used to cap InAs/GaAs QDs in an effort to extend its emission wavelength to the technologically interesting 1.3-155 \xm region [59][60][61][62][63][64]. For InAs/ InP QDs, capping materials other than InP, like InGaAsP, have also successfully been used for laser applications [65][66][67].…”

Section: Capping With Different Materialsmentioning

confidence: 99%

“…This substrate orientation is very attractive for laser applications because, in comparison with InAs dot formation on conventional (100) InP substrates, a higher density of dots having a smaller size dispersion has been achieved on (311)B InP substrates [65,66]. Indeed, room temperature lasers with low threshold current density emitting at 1.5 \xm were recently demonstrated [67].…”

Section: Capping With Lattice-matched Layersmentioning

confidence: 99%

“…The QDs were formed by depositing 2.1 (100) equivalent MLs of InAs on both InP and Ino.87Gao.13Aso.285Po.715 (lattice matched to InP) buffer layers. In order to make the analysis easier, a high As beam equivalent pressure was supplied to the surface during the InAs deposition to favour the formation of large QDs [66]. After island formation, a 30 s growth interruption under As flux was performed before the growth of the capping layer.…”

Section: Double Capping Processmentioning

confidence: 99%

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InAs Quantum Dot Formation Studied at the Atomic Scale by Cross-sectional Scanning Tunnelling Microscopy

Ulloa

Offermans

Koenraad

2008

Handbook of Self Assembled Semiconductor Nanostructures for Novel Devices in Photonics and Electronics

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Introduction Quantum dot formationSelf-assembled quantum dots (QDs) have attracted much attention in the last years [1,2]. These nanostructures are very interesting from a scientific point of view because they form nearly ideal zero-dimensional systems in which quantum confinement effects become very important. These unique properties also make them very interesting from a technological point of view. For example, InAs QDs are employed in QD lasers [3,4], single electron transistors [5], midinfrared detectors [6,7], single-photon sources [8,9], etc. InAs QDs are commonly created by the Stranski-Krastanov growth mode when InAs is deposited on a substrate with a bigger lattice constant, like GaAs or InP [10]. Above a certain critical thickness of InAs, three-dimensional islands are spontaneously formed on top of a wetting layer (WL) to reduce the strain energy. Once created, the QDs are subsequently capped, a step which is required for any device application.For any application based on InAs QDs, an accurate control of their electronic properties is required. The electron and hole states in the dot are very sensitive to the QD size, shape and composition (as well as to the surrounding material), and therefore an accurate control of the QD structural properties is necessary for applications. This explains the strong effort dedicated in the last years to the structural characterization of QDs [11], which is essential in order to have a deep understanding of the QD formation process. Although a lot of effort has been dedicated to study surface QDs, there are relatively few studies focused on the effect of the capping process [12][13][14][15][16][17][18][19][20]. Some of these studies have already shown significant differences in size, shape and composition between uncapped and capped QDs. For example, an important collapse of the QD height has been reported for InAs/GaAs QDs capped with GaAs [14,15,[17][18][19], revealing the big influence of the capping process on the structural properties of the QDs. Indeed, critical issues affecting the dot take place during capping like dot decomposition, intermixing, segregation, As/P exchange and composition modulation in the capping layer. This means that the real buried QDs must be studied in order to understand the complete QD formation process. Cross-sectional scanning tunnelling microscopy is an especially useful technique for this purpose, because it allows the structure of the capped dots at the atomic scale to be assessed. Cross-sectional scanning tunnelling microscopy (X-STM)The scanning tunnelling microscope is part of the family of scanning probe microscopes, which are able to provide direct real space information of a physical property at the atomic scale. This

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Achievement of High Density InAs Quantum Dots on InP (311)B Substrate Emitting at 1.55 µm

Cited by 35 publications

References 14 publications

Increase of charge-carrier redistribution efficiency in a laterally organized superlattice of coupled quantum dots

Increase of charge-carrier redistribution efficiency in a laterally organized superlattice of coupled quantum dots

Capping of InAs quantum dots grown on (311)B InP studied by cross-sectional scanning tunneling microscopy

InAs Quantum Dot Formation Studied at the Atomic Scale by Cross-sectional Scanning Tunnelling Microscopy

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