Growth of (In,Ga)As/(Al,Ga)As quantum wells on GaAs(110) by MBE

Hey, R.; Trampert, A.; Jahn, U.; Couto, O. D. D.; Santos, P. V.

doi:10.1016/j.jcrysgro.2006.11.291

Cited by 8 publications

(5 citation statements)

References 14 publications

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“…For (Al,Ga)As shells, pronounced exciton localization was observed as well, both by other groups and us, and found to result from Al segregation effects beyond random alloy fluctuations . Even for the growth of planar (In,Ga)As QWs by MBE, it was shown that roughness and composition inhomogeneities are stronger for growth on the (110) plane compared to the more common (001) plane . Another potential origin of exciton localization in these structures are crystal‐phase quantum rings (CPQRs) which form at the intersection of the QW and zincblende/wurtzite (ZB/WZ) interfaces stemming from a polytypic NW core .…”

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confidence: 94%

“…[23][24][25] Even for the growth of planar (In,Ga)As QWs by MBE, it was shown that roughness and composition inhomogeneities are stronger for growth on the (110) plane compared to the more common (001) plane. [26,27] Another potential origin of exciton localization in these structures are crystal-phase quantum rings (CPQRs) which form at the intersection of the QW and zincblende/wurtzite (ZB/ WZ) interfaces stemming from a polytypic NW core. [20] Consequently, we attribute the broad luminescence peaks to the inhomogeneity of the material.…”

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confidence: 99%

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Impact of Outer Shell Structure and Localization Effects on Charge Carrier Dynamics in GaAs/(In,Ga)As Nanowire Core–Shell Quantum Wells

Küpers

Corfdir

Lewis

et al. 2019

Physica Rapid Research Ltrs

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Herein, the charge carrier dynamics in GaAs/(In,Ga)As/(Al,Ga)As core–shell nanowires with different outer shell structures are studied. Localization of charge carriers in the minima of potential fluctuations is shown to govern the recombination processes at low temperatures. At higher temperatures, thermionic emission of carriers from the (In,Ga)As shell quantum well leads to a decrease of the luminescence efficiency for a sample with a GaAs outer shell. This effect can be reduced by introducing an AlAs barrier shell. However, the interfaces to this barrier act as an additional source for nonradiative recombination. These results will help in achieving high luminescence intensities at room temperature of light‐emitting devices based on nanowire shell quantum wells.

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confidence: 94%

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confidence: 99%

Impact of Outer Shell Structure and Localization Effects on Charge Carrier Dynamics in GaAs/(In,Ga)As Nanowire Core–Shell Quantum Wells

Küpers

Corfdir

Lewis

et al. 2019

Physica Rapid Research Ltrs

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“…The first band can be assigned to the In 0.15 Ga 0.85 As QW. The linewidth is larger compared to planar (100) QWs, which is commonly attributed to higher interface roughness resulting from growth in the [110] direction. , The second broader band corresponds to luminescence from the n-type GaAs substrate. The similarity in the PL of the two planar samples rules out a possible contamination of one of the As sources as a reason for the drastic difference in PL intensity between the two NW samples.…”

Section: Resultsmentioning

confidence: 99%

Drastic Effect of Sequential Deposition Resulting from Flux Directionality on the Luminescence Efficiency of Nanowire Shells

Küpers

Lewis

Corfdir

et al. 2021

ACS Appl. Mater. Interfaces

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Core−shell nanowire heterostructures form the basis for many innovative devices. When compound nanowire shells are grown by directional deposition techniques, the azimuthal position of the sources for the different constituents in the growth reactor, substrate rotation, and nanowire self-shadowing inevitably lead to sequential deposition. Here, we uncover for In 0.15 Ga 0.85 As/GaAs shell quantum wells grown by molecular beam epitaxy a drastic impact of this sequentiality on the luminescence efficiency. The photoluminescence intensity of shell quantum wells grown with a flux sequence corresponding to migration enhanced epitaxy, that is, when As and the group-III metals essentially do not impinge at the same time, is more than 2 orders of magnitude higher than for shell quantum wells prepared with substantially overlapping fluxes. Transmission electron microscopy does not reveal any extended defects explaining this difference. Our analysis of photoluminescence transients shows that co-deposition has two detrimental microscopic effects. First, a higher density of electrically active point defects leads to internal electric fields reducing the electron− hole wave function overlap. Second, more point defects form that act as nonradiative recombination centers. Our study demonstrates that the source arrangement of the growth reactor, which is of mere technical relevance for planar structures, can have drastic consequences for the material properties of nanowire shells. We expect that this finding holds good also for other alloy nanowire shells.

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“…The linewidth is larger compared to planar (100) QWs, which is commonly attributed to higher interface roughness resulting from growth in the [110] direction. 27,28 The second broader band corresponds to luminescence from the n-type GaAs substrate. The similarity in the PL of the two planar samples rules out a possible contamination of one of the As sources as a reason for the drastic difference in PL intensity between the two NW samples.…”

Section: Resultsmentioning

confidence: 99%

Drastic effect of sequential deposition resulting from flux directionality on the luminescence efficiency of nanowire shells

Küpers¹,

Lewis²,

Corfdir³

et al. 2021

Preprint

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Core-shell nanowire heterostructures form the basis for many innovative devices. When compound nanowire shells are grown by directional deposition techniques, the azimuthal position of the sources for the different constituents in the growth reactor, substrate rotation, and nanowire self-shadowing inevitably lead to sequential deposition. Here, we uncover for In 0.15 Ga 0.85 As/GaAs shell quantum wells grown by molecular beam epitaxy a drastic impact of this sequentiality on the luminescence efficiency. The photoluminescence intensity of shell quantum wells grown with a flux sequence corresponding to migration enhanced epitaxy, i. e. when As and the group-III metals essentially do not impinge at the same time, is more than two orders of magnitude higher than for shell quantum wells prepared with substantially overlapping fluxes. Transmission electron microscopy does not reveal any extended defects explaining this difference. Our analysis of photoluminescence transients shows that codeposition has two detrimental microscopic effects. First, a higher density of electrically active point defects leads to internal electric fields reducing the electron-hole wave function overlap. Second, more point defects form that act as nonradiative recom-bination centers. Our study demonstrates that the source arrangement of the growth reactor, which is of mere technical relevance for planar structures, can have drastic consequences for the materials properties of nanowire shells. We expect that this finding holds also for other alloy nanowire shells.

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Growth of (In,Ga)As/(Al,Ga)As quantum wells on GaAs(110) by MBE

Cited by 8 publications

References 14 publications

Impact of Outer Shell Structure and Localization Effects on Charge Carrier Dynamics in GaAs/(In,Ga)As Nanowire Core–Shell Quantum Wells

Impact of Outer Shell Structure and Localization Effects on Charge Carrier Dynamics in GaAs/(In,Ga)As Nanowire Core–Shell Quantum Wells

Drastic Effect of Sequential Deposition Resulting from Flux Directionality on the Luminescence Efficiency of Nanowire Shells

Drastic effect of sequential deposition resulting from flux directionality on the luminescence efficiency of nanowire shells

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