Exciton-phonon coupling channels in a ‘strain-free’ GaAs droplet epitaxy single quantum dot

Lee, Song ee; Yeo, Inah; Jo, Min Kyung; Jeong, Young Woo; Kim, Tae Geun; Kim, Jong Su; Yi, Kyung–Soo; Han, Il Ki; Song, Jin Dong

doi:10.1016/j.cap.2018.04.003

Cited by 6 publications

(4 citation statements)

References 46 publications

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“…[ 12 , 16 , 22 , 23 ]. The flexibility of droplet epitaxy makes it an advanced growth technique that is particularly attractive for use in the formation of single QDs [ 22 , 24 , 25 ].…”

Section: Introductionmentioning

confidence: 99%

Independent Control Over Size and Surface Density of Droplet Epitaxial Nanostructures Using Ultra-Low Arsenic Fluxes

et al. 2021

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Modern and future nanoelectronic and nanophotonic applications require precise control of the size, shape and density of III-V quantum dots in order to predefine the characteristics of devices based on them. In this paper, we propose a new approach to control the size of nanostructures formed by droplet epitaxy. We reveal that it is possible to reduce the droplet volume independently of the growth temperature and deposition amount by exposing droplets to ultra-low group-V flux. We carry out a thorough study of the effect of arsenic pressure on the droplet characteristics and demonstrate that indium droplets with a large initial size (>100 nm) and a low surface density (<108 cm−2) are able to shrink to dimensions appropriate for quantum dot applications. Small droplets are found to be unstable and difficult to control, while larger droplets are more resistive to arsenic flux and can be reduced to stable, small-sized nanostructures (~30 nm). We demonstrate the growth conditions under which droplets transform into dots, ring and holes and describe a mechanism of this transformation depending on the ultra-low arsenic flux. Thus, we observe phenomena which significantly expand the capabilities of droplet epitaxy.

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“…[ 12 , 16 , 22 , 23 ]. The flexibility of droplet epitaxy makes it an advanced growth technique that is particularly attractive for use in the formation of single QDs [ 22 , 24 , 25 ].…”

Section: Introductionmentioning

confidence: 99%

Independent Control Over Size and Surface Density of Droplet Epitaxial Nanostructures Using Ultra-Low Arsenic Fluxes

et al. 2021

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“…Inhomogeneous line broadening at low temperature is ascribed to spectral diffusion [ 24 , 30 , 82 , 83 , 84 , 85 ] induced by the presence of charged defects nearby the QDs [ 86 ] and is specific to the excitonic complex in study [ 87 , 88 ]. Finally, at higher temperature, the photoluminescence of individual QDs broadens and quenches owing to phonon interactions [ 89 , 90 , 91 ].…”

Section: Introductionmentioning

confidence: 99%

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.

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“…Inhomogeneous line broadening at low temperature is ascribed to spectral diffusion [11,17,[65][66][67][68]induced by the presence of charged defects nearby the QDs [69] and is specific of the excitonic complex in study [70,71]. Finally, at larger temperature, the photoluminescence of individual QDs broadens and quenches owing to phonon interactions [72][73][74].…”

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

Exciton-phonon coupling channels in a ‘strain-free’ GaAs droplet epitaxy single quantum dot

Cited by 6 publications

References 46 publications

Independent Control Over Size and Surface Density of Droplet Epitaxial Nanostructures Using Ultra-Low Arsenic Fluxes

Independent Control Over Size and Surface Density of Droplet Epitaxial Nanostructures Using Ultra-Low Arsenic Fluxes

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

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