Comparative Chemico-Physical Analyses of Strain-Free GaAs/Al0.3Ga0.7As Quantum Dots Grown by Droplet Epitaxy

Yeo, Inah; Kim, Doukyun; Lee, Kyu‐Tae; Kim, Jong Su; Song, Jin Dong; Park, Chul‐Hong; Han, Il Ki

doi:10.3390/nano10071301

Cited by 7 publications

(5 citation statements)

References 38 publications

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“…This picture corresponds very well to what is commonly observed in strain-free, III-V QDs: the presence of geometrical asymmetries in the confining potential breaks the invariance of the Hamiltonian for rotations around the vertical growth axis [ 33 , 34 , 37 , 75 , 78 , 97 , 98 ]. More precisely, e-h spin–spin interaction for the X state lifts the degeneracy of the corresponding energy level and leads to two linearly polarized PL components, depending on which recombination path is radiating.…”

Section: Resultssupporting

confidence: 82%

“…Within this class of QDs, droplet epitaxy (DE) [ 10 , 13 , 14 ] and droplet etching [ 9 , 15 , 16 ] (alternative growth protocols to Stranski–Krastanov for strain-free III–V-based semiconductor nanostructures), enabled the fabrication of state-of-the-art devices such as lasers [ 17 , 18 , 19 , 20 , 21 ] and quantum emitters, including single-photon sources [ 22 , 23 , 24 , 25 , 26 ] and entangled photons [ 9 , 27 , 28 , 29 , 30 ] with electrical injection [ 31 ]. The versatility of this method allowed to grow many different semiconductor alloys (GaInSb [ 32 ], AlGaAs [ 33 , 34 , 35 , 36 , 37 ], InGaAs [ 38 , 39 , 40 , 41 , 42 , 43 , 44 ], and InGaP [ 26 , 45 , 46 ]), forming a plethora of nanostructures [ 47 ] such as quantum dots (QDs); QDs diads [ 48 , 49 , 50 ]; multiple-concentric quantum rings [ 18 , 23 , 51 , 52 ...…”

Section: Introductionmentioning

confidence: 99%

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Exciton Dynamics in Droplet Epitaxial Quantum Dots Grown on (311)A-Oriented Substrates

et al. 2020

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Droplet epitaxy allows the efficient fabrication of a plethora of 3D, III–V-based nanostructures on different crystalline orientations. Quantum dots grown on a (311)A-oriented surface are obtained with record surface density, with or without a wetting layer. These are appealing features for quantum dot lasing, thanks to the large density of quantum emitters and a truly 3D lateral confinement. However, the intimate photophysics of this class of nanostructures has not yet been investigated. Here, we address the main optical and electronic properties of s-shell excitons in individual quantum dots grown on (311)A substrates with photoluminescence spectroscopy experiments. We show the presence of neutral exciton and biexciton as well as positive and negative charged excitons. We investigate the origins of spectral broadening, identifying them in spectral diffusion at low temperature and phonon interaction at higher temperature, the presence of fine interactions between electron and hole spin, and a relevant heavy-hole/light-hole mixing. We interpret the level filling with a simple Poissonian model reproducing the power excitation dependence of the s-shell excitons. These results are relevant for the further improvement of this class of quantum emitters and their exploitation as single-photon sources for low-density samples as well as for efficient lasers for high-density samples.

show abstract

Section: Resultssupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Exciton Dynamics in Droplet Epitaxial Quantum Dots Grown on (311)A-Oriented Substrates

et al. 2020

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show abstract

“…This picture corresponds very well to what is commonly observed in strain-free, III-V QDs: the presence of geometrical asymmetries in the confining potential breaks the invariance of the hamiltonian for rotations around the vertical growth axis [20,21,24,58,61,76,77]. More precisely, e-h spin-spin interaction for the X state lifts the degeneracy of the corresponding energy level and leads to two linearly polarised PL components depending on which recombination path is radiating.…”

Section: E-h Spin Fine Interaction: Fine Structure Splittingsupporting

confidence: 83%

“…The continuous development of droplet epitaxy (DE) [1][2][3] as growth protocol for III-V-based semiconductor nanostructures enabled the fabrication of state-of-the-art devices such as lasers [4][5][6][7][8] and quantum emitters, including single photon sources [9][10][11][12][13] and entangled photons [14][15][16][17] with electrical injection [18]. The versatility of this method allowed to grow many different semiconductor alloys (GaInSb[19], AlGaAs [20][21][22][23][24], InGaAs [25][26][27][28][29][30][31] InGaP [13,32,33]), forming a plethora of nanostructures [34] such as quantum dots (QDs), multiple-concentric quantum rings [5,10,[35][36][37][38][39][40], coupled structures such as ring-on-a-disk [41], dot in-a-ring [42] or dot-on-a-disk [43], as well as elongated structur...…”

Section: Introductionmentioning

confidence: 99%

Exciton Dynamics in Droplet Epitaxial Quantum Dots Grown on (311)A Oriented Substrates

Abbarchi¹,

Mano²,

Kuroda³

et al. 2020

Preprint

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Droplet epitaxy allows the efficient fabrication of a plethora of 3D, III-V-based nanostructures on different crystalline orientations. Quantum dots grown on (311)A-oriented surface are obtained with record surface density, with or without a wetting layer. These are appealing features for quantum-dot lasing, thanks to the large density of quantum emitters and a truly 3D lateral confinement. However, the intimate photophysics of this class of nanostructures has not yet been investigated. Here we address the main optical and electronic properties of s-shell excitons in individual quantum dots grown on (311)A substrates with photoluminescence spectroscopy experiments. We show the presence of neutral exciton and biexciton as well as positive and negative charged excitons. We investigate the origins of spectral broadening, identifying them in spectral diffusion at low temperature and phonon-interaction at higher temperature, the presence of fine interactions between electron and hole spin, and a relevant heavy-hole/light-hole mixing. We interpret the level filling with a simple Poissonian model reproducing the power excitation dependence of the s-shell excitons. These results are relevant for the further improvement of this class of quantum emitters and their exploitation as single photon sources for low density samples as well as for efficient lasers for high density samples.

show abstract

“…GaAs and AlGaAs have a similar lattice constant making it impossible to grow GaAs QDs in SK mode. Interestingly, droplet epitaxy is capable of fabricating strain-free GaAs QDs on AlGaAs [ 83 , 84 , 85 , 86 ]. Initially an AlGaAs buffer layer is grown on top a GaAs substrate at a temperature of 580–600 °C.…”

Section: Strain-free Gaas/algaas Deqdsmentioning

confidence: 99%

Atomic-Scale Characterization of Droplet Epitaxy Quantum Dots

Gajjela

Koenraad

2021

Nanomaterials

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The fundamental understanding of quantum dot (QD) growth mechanism is essential to improve QD based optoelectronic devices. The size, shape, composition, and density of the QDs strongly influence the optoelectronic properties of the QDs. In this article, we present a detailed review on atomic-scale characterization of droplet epitaxy quantum dots by cross-sectional scanning tunneling microscopy (X-STM) and atom probe tomography (APT). We will discuss both strain-free GaAs/AlGaAs QDs and strained InAs/InP QDs grown by droplet epitaxy. The effects of various growth conditions on morphology and composition are presented. The efficiency of methods such as flushing technique is shown by comparing with conventional droplet epitaxy QDs to further gain control over QD height. A detailed characterization of etch pits in both QD systems is provided by X-STM and APT. This review presents an overview of detailed structural and compositional analysis that have assisted in improving the fabrication of QD based optoelectronic devices grown by droplet epitaxy.

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Comparative Chemico-Physical Analyses of Strain-Free GaAs/Al0.3Ga0.7As Quantum Dots Grown by Droplet Epitaxy

Cited by 7 publications

References 38 publications

Exciton Dynamics in Droplet Epitaxial Quantum Dots Grown on (311)A-Oriented Substrates

Exciton Dynamics in Droplet Epitaxial Quantum Dots Grown on (311)A-Oriented Substrates

Exciton Dynamics in Droplet Epitaxial Quantum Dots Grown on (311)A Oriented Substrates

Atomic-Scale Characterization of Droplet Epitaxy Quantum Dots

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