Luminescence properties of dilute bismide systems

Breddermann, B.; Bäumner, Ada; Koch, S. W.; Ludewig, Peter; Stolz, W.; Volz, Kerstin; Hader, J.; Moloney, Jerome V.; Broderick, Christopher A.; O’Reilly, Eoin P.

doi:10.1016/j.jlumin.2014.04.012

Cited by 9 publications

(7 citation statements)

References 17 publications

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“…IV and Fig. 2 show that the E g reduction closest to the 60 − 90 meV/%Bi range of experimental values found in the literature 2,[72][73][74] correspond to the isolated Bi atom and cluster arrangements: Our band gap reduction found for the isolated Bi atom arrangement agrees well with measurements by Huang et al 74 (62 meV/%Bi) and Breddermann et al 72 (60 − 70 meV/%Bi) while our results for the cluster arrangement is in line with measurements by Francoeur et al 2 (88 meV/%Bi) and Tixier et al 73 (84 meV/%Bi). Nevertheless, these are not the most favorable total energy states, which may be due to fixing the size of the supercell.…”

Section: B Bi Complexessupporting

confidence: 74%

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Configuration dependence of band-gap narrowing and localization in diluteGaAs1−xBixalloys

et al. 2016

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Anion substitution with bismuth (Bi) in III-V semiconductors is an effective method for experimental engineering of the band gap Eg at low Bi concentrations (≤ 2%), in particular in gallium arsenide (GaAs). The inverse Bi-concentration dependence of Eg has been found to be linear at low concentrations x and dominated by a valence band-defect level anticrossing between As and Bi occupied p levels. Predictive models for the valence band hybridization require a first-principle understanding which can be obtained by density functional theory with the main challenges being the proper description of Eg and the spin-orbit coupling. By using an efficient method to include these effects, it is shown here that at high concentrations Eg is modified mainly by a Bi-Bi p orbital interaction and by the large Bi atom-induced strain. In particular, we find that at high concentrations the Bi-Bi interactions depend strongly on model periodic cluster configurations, which is not captured by tight-binding models. Averaging over various configurations supports the defect level broadening picture. This points to the role of different atomic configurations obtained by varying the experimental growth conditions in engineering arsenide band gaps, in particular for telecommunication laser technology.

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Section: B Bi Complexessupporting

confidence: 74%

“…Straight lines were fitted through the data points and the value for pure GaAs. In addition, we included results from PL measurements 72 as red stars to compare our theoretical data with experiment.…”

Section: B Bi Complexesmentioning

confidence: 99%

Configuration dependence of band-gap narrowing and localization in diluteGaAs1−xBixalloys

et al. 2016

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“…This is expected since an increase of the lattice constant alters the edges of the first Brillouin zone. The computed band gap narrowing of the SQS (72 meV/ %Bi) is in good agreement with experimental results (60 − 70 meV) 26 .…”

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confidence: 88%

Valence band splitting in bulk dilute bismides

Bannow

Bădescu

Hader

et al. 2017

Applied Physics Letters

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The electronic structure of bulk GaAs 1−x Bi x systems for different atomic configurations and Bi concentrations is calculated using density functional theory. The results show a Bi-induced splitting between the light-hole and heavy-hole bands at the Γ-point. We find a good agreement between our calculated splittings and experimental data. The magnitude of the splitting strongly depends on the local arrangement of the Bi atoms but not on the uni-directional lattice constant of the supercell. The additional influence of external strain due to epitaxial growth on GaAs substrates is studied by fixing the in-plane lattice constants.The following article has been submitted to Applied Physics Letters. If it is published, it will be found online at http://apl.aip.orgThe incorporation of relatively small concentrations of bismuth into semiconductor compounds is of growing interest because substitution of Bi not only allows for the engineering of the band gap E g 1 of III-V semiconductors but also of the spin-orbit splitting ∆ so 2 . It has been proposed that making ∆ so larger than E g should lead to a decrease of the nonradiative Auger losses which is important to improve the output characteristics of semiconductor lasers 3,4 .In addition to the intrinsic splitting between the spin-orbit split-off band (so) and the top-most valence bands, the degeneracy of the heavy-hole (hh) and light-hole (lh) bands at the Γ-point can also be lifted by symmetry reductions. A wellknown example is the valence band splitting (VBS) in III-V semiconductors caused by strain due to lattice-mismatched growth 5 . Experimentally, VBS was observed for GaAs 1−x Bi x layers grown lattice-mismatched on GaAs substrates 1,6,7 . To analyze the observations, Batool et al. 6 extracted the shear deformation potential for a Bi content up to x = 10.4 %. As previously shown for dilute nitrides 8 , the authors find that the shear deformation potential depends on the content of the substitute. However, in the case of GaAs 1−x N x the VBS shows a bowing which is absent for GaAs 1−x Bi x . In addition, a VBS of bulk GaAs 1−x Bi x has been observed in tight-binding calculations by Usman et al. 9 even though the authors do not further comment on it. They find an increase of the splitting in the case of compressive strain 10 which slightly underestimates the splitting reported by Batool et al. 6 .To systematically study Bi induced VBS, we use density functional theory (DFT) for the calculation of the band structures of dilute bismide semiconductors. Remarkably, our results show that a large VBS in the range of tens to more than hundred meV exists for bulk systems without any external strain. The magnitude of the splitting strongly depends on the local atomic arrangement of the Bi atoms in the GaAs lattice. Similar cluster-induced VBS has previously also been reported for GaAs 1−x N x 11 . For a given atomic configuration, a) Electronic mail: lars.bannow@physik.uni-marburg.de the VBS can be further increased when a lattice-mismatched growth is modeled by allowing ...

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“…Most of them use molecular beam epitaxy followed by related optical characterization of the bandedge [52,53]. Some theoretical works [54,55] have also been done since the 12-band effective mass Hamiltonian method [56][57][58][59][60] was proposed by O'Reilly based on the VBAC model. However, not much progress has been made on the study of GaBiAs QDs.…”

Section: Iii-v Dilute Nitride/bismide Quantum Dots and Wellsmentioning

confidence: 99%

“…Both bulk and GaBiAs quantum wells have attracted lot of interest recently. Some theoretical work [54,55] has also been done since the 12-band k•p model [56][57][58][59][60] was proposed by O'Reilly based on the VBAC model. However, not much progress has been made on the study of GaBiAs QDs.…”

Section: Introductionmentioning

confidence: 99%

Semiconductor quantum nanostructures for optoelectronic applications

Bose¹

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T hank you, dear reader, I acknowledge you for reading my thesis! It adds value to the many hours spent writing this, and my journey of over four years leading to it.A great many people have had immense contributions directly or indirectly, in the evolution of this thesis to its current form and shaping my doctoral career in general.My deepest gratitude is to my supervisor, Assoc. Prof. Fan Weijun. I have been amazingly fortunate to have a supervisor who believed in me and gave the freedom to explore uncharted waters, but at the same time extended timely guidance to recover whenever my steps faltered. His patience and support has helped me evolve as an independent researcher. My co-supervisor, Prof. Zhang Dao Hua, has been a support figure with invaluable research insights. I am deeply grateful to him for the discussions during meetings, supporting my cause to access reserved characterization tools, and ready financial support.

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Luminescence properties of dilute bismide systems

Cited by 9 publications

References 17 publications

Configuration dependence of band-gap narrowing and localization in diluteGaAs1−xBixalloys

Configuration dependence of band-gap narrowing and localization in diluteGaAs1−xBixalloys

Valence band splitting in bulk dilute bismides

Semiconductor quantum nanostructures for optoelectronic applications

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