First-Principles Calculations of Band Offsets at Heterovalent 
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Greene‐Diniz, Gabriel; Grüning, Myrta

doi:10.1103/physrevapplied.10.044052

Cited by 3 publications

(1 citation statement)

References 76 publications

(119 reference statements)

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“…In our design, we exploit the ability of Ge/III-V heterostructures to induce epitaxial stress in the Ge thin-film and simultaneously provide sufficient optical and carrier confinement so as to realize a practical lasing structure. A first-principles computation of the Ge/InAlAs electronic structure reveals band offsets ≥ 0.56 ± 0.1 eV at the ε-Ge/InxAl1-xAs heterointerface, 42 corroborated with our experimental band offset results. Utilizing a MBE growth process, discussed below, we have demonstrated the feasibility of integrating the tensile-strained InxGa1-xAs/ε-Ge/InxGa1-xAs QW laser structure on GaAs substrate.…”

Section: -Ge Quantum-well Laser Design and Modeling: -Selection Of T...supporting

confidence: 87%

Design, Theoretical, and Experimental Investigation of Tensile-Strained Germanium Quantum-Well Laser Structure

Hudait

Murphy-Armando²,

Saladukha

et al. 2021

ACS Appl. Electron. Mater.

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Strain and bandgap engineered epitaxial germanium (ε-Ge) quantum-well (QW) laser structures were investigated on GaAs substrates theoretically and experimentally for the first time. In this design, we exploit the ability of InGaAs layer to simultaneously provide tensile strain in Ge (0.7% to 1.96%) and sufficient optical and carrier confinement. The direct band-to-band gain, threshold current density (Jth) and loss mechanisms that dominate in the ε-Ge QW laser structure, were calculated using first-principles-based 30-band k.p electronic structure theory, at injected carrier concentrations from 3x10 18 cm -3 to 9x10 19 cm -3 . The higher strain in ε-Ge QW increases the gain at higher wavelengths; however, a decreasing thickness is required by higher strain due to critical layer thickness for avoiding strain relaxation. In addition, we predict that a Jth of 300 A/cm 2 can be reduced to <10 A/cm 2 by increasing strain from 0.2% to 1.96% in ε-Ge lasing media. The measured room temperature photoluminescence spectroscopy demonstrated direct bandgap optical emission from the conduction band at valley to heavy-hole (0.6609 eV) from 1.6% tensile strained Ge/In0.24Ga0.76As heterostructure grown by molecular beam epitaxy, is in agreement with the value calculated using 30-band k.p

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Section: -Ge Quantum-well Laser Design and Modeling: -Selection Of T...supporting

confidence: 87%

Design, Theoretical, and Experimental Investigation of Tensile-Strained Germanium Quantum-Well Laser Structure

Hudait

Murphy-Armando²,

Saladukha

et al. 2021

ACS Appl. Electron. Mater.

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Mapping the Interfacial Electronic Structure of Strain-Engineered Epitaxial Germanium Grown on In_xAl_1–xAs Stressors

et al. 2022

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The indirect nature of silicon (Si) emission currently limits the monolithic integration of photonic circuitry with Si electronics. Approaches to circumvent the optical shortcomings of Si include band structure engineering via alloying (e.g., Si x Ge1–x–y Sn y ) and/or strain engineering of group IV materials (e.g., Ge). Although these methods enhance emission, many are incapable of realizing practical lasing structures because of poor optical and electrical confinement. Here, we report on strong optoelectronic confinement in a highly tensile-strained (ε) Ge/In0.26Al0.74As heterostructure as determined by X-ray photoemission spectroscopy (XPS). To this end, an ultrathin (∼10 nm) ε-Ge epilayer was directly integrated onto the In0.26Al0.74As stressor using an in situ, dual-chamber molecular beam epitaxy approach. Combining high-resolution X-ray diffraction and Raman spectroscopy, a strain state as high as ε ∼ 1.75% was demonstrated. Moreover, high-resolution transmission electron microscopy confirmed the highly ordered, pseudomorphic nature of the as-grown ε-Ge/In0.26Al0.74As heterostructure. The heterointerfacial electronic structure was likewise probed via XPS, revealing conduction- and valence band offsets (ΔE C and ΔE V) of 1.25 ± 0.1 and 0.56 ± 0.1 eV, respectively. Finally, we compare our empirical results with previously published first-principles calculations investigating the impact of heterointerfacial stoichiometry on the ε-Ge/In x Al1–x As energy band offset, demonstrating excellent agreement between experimental and theoretical results under an As0.5Ge0.5 interface stoichiometry exhibiting up to two monolayers of heterointerfacial As–Ge diffusion. Taken together, these findings reveal a new route toward the realization of on-Si photonics.

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Lattice matched GeSn/InAlAs heterostructure: role of Sn in energy band alignment, atomic layer diffusion and photoluminescence

Karthikeyan¹,

Joshi²,

Zhao³

et al. 2023

J. Mater. Chem. C

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First-Principles Calculations of Band Offsets at Heterovalent ε - Ge/InxAl1−xAs

Cited by 3 publications

References 76 publications

Design, Theoretical, and Experimental Investigation of Tensile-Strained Germanium Quantum-Well Laser Structure

Design, Theoretical, and Experimental Investigation of Tensile-Strained Germanium Quantum-Well Laser Structure

Mapping the Interfacial Electronic Structure of Strain-Engineered Epitaxial Germanium Grown on In_xAl_1–xAs Stressors

Lattice matched GeSn/InAlAs heterostructure: role of Sn in energy band alignment, atomic layer diffusion and photoluminescence

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First-Principles Calculations of Band Offsets at Heterovalent ε - Ge/InxAl1−xAs

Cited by 3 publications

References 76 publications

Design, Theoretical, and Experimental Investigation of Tensile-Strained Germanium Quantum-Well Laser Structure

Design, Theoretical, and Experimental Investigation of Tensile-Strained Germanium Quantum-Well Laser Structure

Mapping the Interfacial Electronic Structure of Strain-Engineered Epitaxial Germanium Grown on InxAl1–xAs Stressors

Lattice matched GeSn/InAlAs heterostructure: role of Sn in energy band alignment, atomic layer diffusion and photoluminescence

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Product

Resources

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Mapping the Interfacial Electronic Structure of Strain-Engineered Epitaxial Germanium Grown on In_xAl_1–xAs Stressors