Polarization resolved photoluminescence in GaAs1−xBix/GaAs quantum wells

Balanta, M.A.G.; Gordo, V. Orsi; Carvalho, Aleksandra; Puustinen, Janne; Alghamdi, Haifa Mohammed; Henini, M.; Galeti, H. V. A.; Guina, Mircea; Gobato, Y. Galvão

doi:10.1016/j.jlumin.2016.10.008

Cited by 7 publications

(10 citation statements)

References 21 publications

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“…The accuracy of the tight-binding model was verified against the available experimental data sets in a number published studies including on band-gap variation of the GaBixAs1−x bulk material as a function of Bi composition with 39 and without 29 strain, and GaBiAs/GaAs quantum well structures. 40 Subsequent studies based on DFT model [41][42][43] and experimental measurements 29,39,[44][45][46][47][48][49] demonstrated a good agreement with the simulated results, which again affirmed the high-level accuracy of our atomistic techniques. We also note that in contrast to the simplified models used in the literature such band anti-crossing method, effective-mass and k • p models 37,50,50,51 which have been quite successful to qualitatively model GaBixAs1−x based photonic devices, the atomistic tight-binding simulations employed here explicitly represent the nanowire geometries with atomic resolution.…”

supporting

confidence: 63%

Tunable band-gap and isotropic light absorption from bismuth-containing GaAs core$-$shell and multi$-$shell nanowires

Usman

2020

Preprint

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Semiconductor core−shell nanowires based on the GaAs substrate are building blocks of many photonic, photovoltaic and electronic devices, thanks to the associated direct band-gap and the highly tunable optoelectronic properties. The selection of a suitable material system is crucial for custom designed nanowires tailored for optimised device performance. The bismuth containing GaAs materials are an imminent class of semiconductors which not only enable an exquisite control over the alloy strain and electronic structure but also offer the possibility to suppress internal loss mechanisms in photonic devices. Whilst the experimental efforts to incorporate GaBixAs1−x alloys in the nanowire active region are still in primitive stage, the theoretical understanding of the optoelectronic properties of such nanowires is only rudimentary. This work elucidates and quantifies the role of nanowire physical attributes such as its geometry parameters and bismuth incorporation in designing light absorption wavelength and polarisation response. Based on multi-million atom tight-binding simulations of the GaBixAs1−x/GaAs core−shell and GaAs/GaBixAs1−x/GaAs multi−shell nanowires, our results predict a large tuning of the absorption wavelength, ranging from 0.9 µm to 1.6 µm, which can be controlled by engineering either Bi composition or nanowire diameter. The analysis of the strain profiles indicates a tensile character leading to significant light-hole mixing in the valence band states. This offers a possibility to achieve polarisation-insensitive light interaction, which is desirable for several photonic devices involving amplification and modulation of light. Furthermore, at low Bi compositions, the carrier confinement is quasi type-II, which further broadens the suitability of these nanowires for myriad applications demanding large carrier separations. The presented results provide a systematic and comprehensive understanding of the GaBixAs1−x nanowire properties and highlight new possibilities for future technologies in photonics, quantum optics and solar energy harvesting.

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supporting

confidence: 63%

Tunable band-gap and isotropic light absorption from bismuth-containing GaAs core$-$shell and multi$-$shell nanowires

Usman

2020

Preprint

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“…The experimental and theoretical investigations of both unstrained and strained bulk GaBi x As 1−x alloys have shown promising properties with increasing Bi fractions such as a large band gap reduction [5,[11][12][13], a crossover between the band gap and spin split-off energies [12][13][14], and the possibility of lattice-matched growth on a GaAs substrate [15]. These novel characteristics have sparked a remarkable experimental interest in designing devices based on GaBi x As 1−x /GaAs quantum well (QW) structures, which could offer optimised performance [3,[16][17][18][19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Large-scale atomistic simulations demonstrate dominant alloy disorder effects in GaBixAs1−x/GaAs multiple quantum wells

Usman

2018

Phys. Rev. Materials

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Bismide semiconductor materials and heterostructures are considered a promising candidate for the design and implementation of photonic, thermoelectric, photovoltaic, and spintronic devices. This work presents a detailed theoretical study of the electronic and optical properties of stronglycoupled GaBixAs1−x/GaAs multiple quantum well (MQW) structures. Based on a systematic set of large-scale atomistic tight-binding calculations, our results reveal that the impact of atomic-scale fluctuations in alloy composition is stronger than the inter-well coupling effect, and plays an important role in the electronic and optical properties of MQW structures. Independent of QW geometry parameters, alloy disorder leads to a strong confinement of charge carriers, a large broadening of the hole energies, and a red shift in the ground-state transition wavelength. Polarisation-resolved optical transition strengths exhibit a striking effect of disorder, where the inhomogeneous broadening could exceed an order of magnitude for MQWs, in comparison to a factor of about three for single quantum wells. The strong influence of alloy disorder effects persists when small variations in the size and composition of MQWs typically expected in a realistic experimental environment are considered. The presented results highlight the limited scope of continuum methods and emphasise on the need for large-scale atomistic approaches to design devices with tailored functionalities based on the novel properties of bismide materials. arXiv:1712.06720v2 [cond-mat.mtrl-sci]

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“…Similar results were observed in all as-grown and post-thermal annealed GaPN samples with different N concentrations. These results evidence important effect of exciton localization [51,52] in GaPN layers probably due to composition variation which cannot be changed after thermal annealing treatment. We have also investigated the polarization resolved PL for as-grown and annealed layers.…”

Section: Magneto-plmentioning

confidence: 73%

Effects of nitrogen incorporation and thermal annealing on the optical and spin properties of GaPN dilute nitride alloys

Balanta

Oliveira

Albalawi

et al. 2020

Journal of Alloys and Compounds

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Here, we report on the structural, optical and magneto-optical properties of as-grown and thermal annealed GaPN thin films containing different N concentrations grown by Solid-Source Molecular Beam Epitaxy on GaP substrates. A wide range of characterization techniques were used to investigate the effect of N incorporation and thermal annealing effect of GaPN/GaP epilayers for a N content between 0.5% and 3%. Our results have shown that as we increase the N content the PL peak energy presents a red shift which is explained by a band gap reduction. However, important effects of exciton localization on optical properties were also evidenced from cw and time resolved PL (PLRT) and magneto-PL. Our results have demonstrated that as the concentration of N is increased, exciton localization effect is enhanced. A substantial improvement of the optical quality and spin properties of the epilayers has been observed after thermal annealing which are significantly more important for samples with higher nitrogen contents.

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Polarization resolved photoluminescence in GaAs1−xBix/GaAs quantum wells

Cited by 7 publications

References 21 publications

Tunable band-gap and isotropic light absorption from bismuth-containing GaAs core$-$shell and multi$-$shell nanowires

Tunable band-gap and isotropic light absorption from bismuth-containing GaAs core$-$shell and multi$-$shell nanowires

Large-scale atomistic simulations demonstrate dominant alloy disorder effects in GaBixAs1−x/GaAs multiple quantum wells

Effects of nitrogen incorporation and thermal annealing on the optical and spin properties of GaPN dilute nitride alloys

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