The potential role of Bismide alloys in future photonic devices

Sweeney, S. J.; Batool, Zahida; Hild, K.; Jin, S. R.; Hosea, T. J. C.

doi:10.1109/icton.2011.5970829

Cited by 47 publications

(56 citation statements)

References 4 publications

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“…This is of significant potential benefit for telecommunication lasers, because it could enable the suppression of the Auger recombination losses which dominate the threshold characteristics of GaInAsP and AlGaInAs lasers. 5,7,10 The strong band gap bowing in GaBi x As 1−x is similar to that observed in GaN x As 1−x , where E g decreases by as much as 150 meV when 1% of As is replaced by N. The band gap reduction in GaN x As 1−x has been well explained using a band-anticrossing (BAC) model. 11 It is well established that replacing a single As atom by N introduces a resonant defect level above the conduction band edge (CBE) in GaAs.…”

Section: Introductionmentioning

confidence: 59%

“…This crossing is technologically important for the design and realization of photonic devices, due to the possibility of suppressing at higher bismuth concentrations the CHSH Auger recombination loss process, whereby a Conduction band electron recombines with a Heavy-hole exciting a second hole into the Spin orbit band from the Heavy-hole band. 5,7,10 …”

Section: A Comparison Of Theory and Experimentsmentioning

confidence: 99%

“…[5][6][7][8] When a small fraction of As is replaced by Bi in GaAs, the energy gap E g decreases rapidly, by ≈90 meV when 1% of As is replaced by Bi. In addition, photoreflectance measurements show that the energy separation, SO , between the spin-split-off valence band and the valence band edge also increases rapidly with Bi composition.…”

Section: Introductionmentioning

confidence: 99%

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Impact of alloy disorder on the band structure of compressively strained GaBixAs1−x

Usman¹,

et al. 2013

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The incorporation of bismuth (Bi) in GaAs results in a large reduction of the band gap energy (E g ) accompanied with a large increase in the spin-orbit splitting energy ( SO ), leading to the condition that SO > E g , which is anticipated to reduce hot-hole producing Auger recombination losses whereby the energy and momentum of a recombining electron-hole pair are given to a second hole which is excited into the spin-orbit band. We theoretically investigate the electronic structure of experimentally grown GaBi x As 1−x samples on (100) GaAs substrates by directly comparing our data with room temperature photomodulated reflectance (PR) measurements. Our atomistic theoretical calculations, in agreement with the PR measurements, confirm that E g is equal to SO for x ≈ 9%. We then theoretically probe the inhomogeneous broadening of the interband transition energies as a function of the alloy disorder. The broadening associated with spin-split-off transitions arises from conventional alloy effects, while the behavior of the heavy-hole transitions can be well described using a valence bandanticrossing model. We show that for the samples containing 8.5% and 10.4% Bi the difficulty in identifying a clear light-hole-related transition energy from the measured PR data is due to the significant broadening of the host matrix light-hole states as a result of the presence of a large number of Bi resonant states in the same energy range and disorder in the alloy. We further provide quantitative estimates of the impact of supercell size and the assumed random distribution of Bi atoms on the interband transition energies in GaBi x As 1−x . Our calculations support a type-I band alignment at the GaBi x As 1−x /GaAs interface, consistent with recent experimental findings.

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Section: Introductionmentioning

confidence: 59%

Section: A Comparison Of Theory and Experimentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Impact of alloy disorder on the band structure of compressively strained GaBixAs1−x

Usman¹,

et al. 2013

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“…[1][2][3] Replacing a small fraction of As by Bi in GaAs leads to a large reduction in band gap energy (E g ), accompanied with a rapid increase in the spin-orbit-splitting energy ð᭝ SO Þ, thereby leading to a ᭝ SO > E g regime. 4,5 This crossing is technologically important as it has been predicted to suppress the dominant efficiency-limiting CHSH Auger loss mechanism, whereby a Conduction band (CB) electron recombines with a Heavy-hole exciting a second hole into the Spin orbit band from the Heavy-hole band.…”

mentioning

confidence: 99%

Atomistic tight-binding study of electronic structure and interband optical transitions in GaBixAs1−x/GaAs quantum wells

Usman¹,

O’Reilly

2014

Applied Physics Letters

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“…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 .…”

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confidence: 99%

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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The potential role of Bismide alloys in future photonic devices

Cited by 47 publications

References 4 publications

Impact of alloy disorder on the band structure of compressively strained GaBixAs1−x

Impact of alloy disorder on the band structure of compressively strained GaBixAs1−x

Atomistic tight-binding study of electronic structure and interband optical transitions in GaBixAs1−x/GaAs quantum wells

Valence band splitting in bulk dilute bismides

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