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Alberi, Kirstin; Beaton, Daniel A.; Mascarenhas, A.

doi:10.1103/physrevb.92.241201

Cited by 14 publications

(16 citation statements)

References 29 publications

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“…7-9, we find a change in relative position of E Bi and the VBM of about 150 meV/%Bi, consistent with Ref. 66, Fig. 2.…”

Section: Electronic Structure Of Bi Pairssupporting

confidence: 91%

“…First, our finding in Fig. 7 that both the valence band maximum (VBM) and the resonant level E Bi have a Bi contribution is consistent with Joshya et al 65 and Alberi et al 66 . Next, Figs.…”

Section: Electronic Structure Of Bi Pairssupporting

confidence: 90%

“…The diffuse Bloch character is indicative of localization effects in the valence band. These findings are consistent with extensive signatures of trap states revealed in the valence band by electromodulated reflectance measurements 65,66 . This corroboration of strain and chemical effects in decreasing E g is consistent with the previous observation from Fig.…”

Section: A Comparison Of Strain and Chemical Effects In Band Gap Narsupporting

confidence: 87%

“…Here, we would like to make a qualitative comparison between the shifts in the energy levels calculated here and those measured in recent experiments on identifying Bi resonant states 65,66 . First, our finding in Fig.…”

Section: Electronic Structure Of Bi Pairsmentioning

confidence: 86%

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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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“…7-9, we find a change in relative position of E Bi and the VBM of about 150 meV/%Bi, consistent with Ref. 66, Fig. 2.…”

Section: Electronic Structure Of Bi Pairssupporting

confidence: 91%

Section: Electronic Structure Of Bi Pairssupporting

confidence: 90%

Section: A Comparison Of Strain and Chemical Effects In Band Gap Narsupporting

confidence: 87%

Section: Electronic Structure Of Bi Pairsmentioning

confidence: 86%

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

et al. 2016

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“…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 %.…”

mentioning

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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Giant bowing of the band gap and spin-orbit splitting energy in GaP1−xBix dilute bismide alloys

Bushell

Broderick

Nattermann

et al. 2019

Sci Rep

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Using spectroscopic ellipsometry measurements on GaP 1− x Bi x /GaP epitaxial layers up to x = 3.7% we observe a giant bowing of the direct band gap ( ) and valence band spin-orbit splitting energy (Δ SO ). (Δ SO ) is measured to decrease (increase) by approximately 200 meV (240 meV) with the incorporation of 1% Bi, corresponding to a greater than fourfold increase in Δ SO in going from GaP to GaP 0.99 Bi 0.01 . The evolution of and Δ SO with x is characterised by strong, composition-dependent bowing. We demonstrate that a simple valence band-anticrossing model, parametrised directly from atomistic supercell calculations, quantitatively describes the measured evolution of and Δ SO with x . In contrast to the well-studied GaAs 1− x Bi x alloy , in GaP 1− x Bi x substitutional Bi creates localised impurity states lying energetically within the GaP host matrix band gap. This leads to the emergence of an optically active band of Bi-hybridised states, accounting for the overall large bowing of and Δ SO and in particular for the giant bowing observed for x ≲ 1%. Our analysis provides insight into the action of Bi as an isovalent impurity, and constitutes the first detailed experimental and theoretical analysis of the GaP 1− x Bi x alloy band structure.

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Direct observation of theE−resonant state inGaAs1−xBix

Cited by 14 publications

References 29 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

Giant bowing of the band gap and spin-orbit splitting energy in GaP1−xBix dilute bismide alloys

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