Structural atomic-scale analysis of GaAs/AlGaAs quantum wires and quantum dots grown by droplet epitaxy on a (311)A substrate

Keizer, JG Joris; Jo, Masafumi; Mano, Takaaki; Noda, Takeshi; Sakoda, Kazuaki; Koenraad, PM Paul

doi:10.1063/1.3589965

Cited by 16 publications

(21 citation statements)

References 19 publications

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“…2,17-20 to measure the band gap and fine excition structure. It is worth mentioning that the quantum dot height decreases from 14 nm when quantum dots are grown by droplet epitaxy on a (001)-oriented GaAs substrate 8 to much smaller value of 2.3 ± 0.6 nm when quantum dots are grown on a (311)A-oriented GaAs substrate 24 . However, the measurement of XSTM 8 and spectroscopy 2,[17][18][19][20] considered in this paper, as well as theory, are all on (001) substrate.…”

Section: Resultsmentioning

confidence: 99%

Geometry of epitaxial GaAs/(Al,Ga)As quantum dots as seen by excitonic spectroscopy

Luo

Zunger

2011

Phys. Rev. B

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It is shown that exciton and multi-exciton emission lines ("spectral barcode") of a quantum dot conceal nontrivial structural information on the shape and size of the dot, information which can be uncovered by comparison with atomistic many-body theory. Application to the newly-established strain-free GaAs quantum dots grown via "droplet epitaxy" onto AlGaAs matrix reveal the shape and size as "seen" by spectroscopy. The results show that the previously determined dot height (∼ 14 nm) as "seen" by cross-sectional scanning tunneling microscopy (XSTM) could not possibly be consistent with the excitonic signature (1.7-1.9 eV), as the latter must reflect a 1-4 nm tall dot. Multi-exciton "barcode" and fine structure spitting suggest GaAs/AlGaAs dots are in Gaussianshape in agreement with XSTM measurement. Both spectroscopy and XSTM measurements were done on GaAs dots capped by the Al0.3Ga0.7As barrier layer. The fact that XSTM sees tall dots and spectroscopy sees short dots is thus not because the dot change its height in one experiment relative to the other, but because different dots must have been used. This was uncovered by theoretical simulation of the experiment showing that the two experiments could not possibly correspond to the same dot.

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Section: Resultsmentioning

confidence: 99%

Geometry of epitaxial GaAs/(Al,Ga)As quantum dots as seen by excitonic spectroscopy

Luo

Zunger

2011

Phys. Rev. B

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“…However, low-level Al defects and Al intermixing have been probed to remain in strain-free GaAs DE QDs [ 11 , 13 , 24 ]. Atomic scale analyses have confirmed a low degree of Al defects in two-dimensional (2D) [ 11 , 25 ] and 3D composition profiles [ 13 ]. These Al remnants modify the electronic and phononic band structures of the GaAs DE QDs, degrading the fidelity of the entangled photons.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2020

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We investigate the quantum confinement effects on excitons in several types of strain-free GaAs/Al 0 . 3 Ga 0 . 7 As droplet epitaxy (DE) quantum dots (QDs). By performing comparative analyses of energy-dispersive X-ray spectroscopy with the aid of a three-dimensional (3D) envelope-function model, we elucidate the individual quantum confinement characteristics of the QD band structures with respect to their composition profiles and the asymmetries of their geometrical shapes. By precisely controlling the exciton oscillator strength in strain-free QDs, we envisage the possibility of tailoring light-matter interactions to implement fully integrated quantum photonics based on QD single-photon sources (SPSs).

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“…On (311)A substrates, Ga droplets etch the substrate by only a few MLs at 200 C, 28 while holes of 12-nm depth were formed at 350 C using In droplets. 29 Figure 1(a) illustrates that etching by Ga is also significant at 300 C with a hole depth of 2 nm.…”

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confidence: 99%

Extremely high-density GaAs quantum dots grown by droplet epitaxy

Mano

Sakuma

et al. 2012

Applied Physics Letters

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We report the fabrication of extremely high-density GaAs quantum dots (QDs) by droplet epitaxy. We investigated the dependence of temperature and coverage on the dot density. As a result, an areal density of 7.3 × 1011 cm−2 was achieved at a growth temperature of 30 °C by controlling the amount of Ga. The QDs showed clear luminescence even when grown at a low temperature of 30 °C.

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Structural atomic-scale analysis of GaAs/AlGaAs quantum wires and quantum dots grown by droplet epitaxy on a (311)A substrate

Abstract: Jo, M.; Mano, T.; Noda, T.; Sakoda, K.; Koenraad, P.M.

Cited by 16 publications

References 19 publications

Geometry of epitaxial GaAs/(Al,Ga)As quantum dots as seen by excitonic spectroscopy

Geometry of epitaxial GaAs/(Al,Ga)As quantum dots as seen by excitonic spectroscopy

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

Extremely high-density GaAs quantum dots grown by droplet epitaxy

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