Three-dimensionally confined excitons and biexcitons in submonolayer-CdSe/ZnSe superlattices

Straussburg, M.; Heitz, R.; Türck, V.; Rodt, Sven; Pohl, Udo W.; Hoffmann, A.; Bimberg, D.; Krestnikov, I. L.; Shchukin, V. A.; Ledentsov, N. N.; Alfërov, Zh. I.; Litvinov, D.; Rosenauer, Andreas; Gerthsen, D.

doi:10.1007/s11664-999-0103-1

Cited by 20 publications

(7 citation statements)

References 33 publications

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“…at the low and much more pronounced at high excitation densities. This temperature-dependent behavior is similar to observations of localized excitons in CdSe islands [10] in a ZnSe matrix. Therefore, we believe that localized carriers in In rich islands are responsible for the observed behavior.…”

Section: Methodssupporting

confidence: 86%

Impact of Structural Properties on the Mechanisms of Optical Amplification in Cubic GaInN

Holst¹,

Hoffmann

Broser

et al. 1999

phys. stat. sol. (b)

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Section: Methodssupporting

confidence: 86%

Impact of Structural Properties on the Mechanisms of Optical Amplification in Cubic GaInN

Holst¹,

Hoffmann

Broser

et al. 1999

phys. stat. sol. (b)

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“…A similar polarization of edge emission has been observed in the case of vertically coupled InGaAs-GaAs Stranski-Krastanow QDs [62]. These obser- The extension of the exciton wavefunction in uncoupled and coupled QD structures was estimated from the diamagnetic behavior for magnetic fields applied parallel to the growth direction [63]. In Fig.…”

Section: Polarization Of Edge Emission and Symmetry Of The Heavy Holesupporting

confidence: 70%

Arrays of Two-Dimensional Islands Formed by Submonolayer Insertions: Growth, Properties, Devices

Krestnikov

Ledentsov

Hoffmann

et al. 2001

phys. stat. sol. (a)

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103

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Ultrathin insertions of a narrow band-gap material in wide band-gap matrices represent a challenging medium in view of aspects of growth phenomena, unique optical properties, and non-trivial approaches for structural characterization. In a very general case ultrathin submonolayer insertions may form arrays of islands due to the principally discrete nature of the growth front. If the islands are large enough, these islands may act as locally formed quantum well (QW) insertions. If, however, the islands' size is comparable to the Bohr radius and the band-gap difference between the insert and the matrix material is large enough, quantum dots (QD) are formed. Realization of the first or the second regime depends on the surface properties of the substrate and the deposit, particularly, on the tensors of the intrinsic surface stress of both materials and on the lattice mismatch. In this work we consider in detail the case of ultrathin CdSe insertions in wide gap ZnMgSSe matrices: that the nominal thickness is chosen below the critical thickness for threedimensional (3D) island formation. We give an overview of the experimental results available for these structures obtained by submonolayer or about-one monolayer CdSe depositions. A comparison with similar phenomena observed in conventional III-V and III-N systems is given and possible growth scenarios are discussed. We also discuss practical device applications of the structures based on ultrathin insertions for non-traditional devices. Examples of resonant waveguiding and lasing in edge geometry, of surface emitting lasers with low finesse cavities, and of broad-miniband high-frequency Esaki-Tsu anti-dot superlattices are given.

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“…In addition the formation of biexcitons and negatively charged excitons shifts the center emission of both QD subsets to lower energy and gives rise to broadening on the low energy side of the PL bands. 21,43,45,[55][56][57] We further investigated the temperature dependence of the PL emission of the bimodal QD distribution. Such measurements provide important information about thermally induced carrier escape and subsequent recapture by strongly localized QD potentials.…”

Section: Resultsmentioning

confidence: 99%

Relaxation dynamics of bimodally distributed CdSe quantum dots

et al. 2007

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We study the dynamical behavior of excitons in a bimodal distribution of CdSe/ ZnSSe quantum dots by intensity dependent, temperature dependent, and time resolved photoluminescence. The effect of exciton localization is investigated, both experimentally and theoretically by identifying transfer mechanisms due to thermalization and redistribution of excitons. We observe a dominant exciton emission from high energy dots ͑QDs1͒ and weaker emission from low energy dots ͑QDs2͒ at 10 K and at low excitation levels. At high excitation densities a CdSe QD-precursor state becomes visible at the high energy side of the QDs1 emission. Temperature dependent photoluminescence studies reveal a thermally activated exciton transfer from QDs1 to QDs2 resulting in an enhanced QDs2 emission above 60 K. Time resolved photoluminescence measurements allow us to estimate the characteristic radiative and nonradiative decay rates as well as the trapping rate from the QD-precursor layer. The experimentally observed photoluminescence is reasonably reproduced using a coupled rate equation model.

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Three-dimensionally confined excitons and biexcitons in submonolayer-CdSe/ZnSe superlattices

Cited by 20 publications

References 33 publications

Impact of Structural Properties on the Mechanisms of Optical Amplification in Cubic GaInN

Impact of Structural Properties on the Mechanisms of Optical Amplification in Cubic GaInN

Arrays of Two-Dimensional Islands Formed by Submonolayer Insertions: Growth, Properties, Devices

Relaxation dynamics of bimodally distributed CdSe quantum dots

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