Experimental Calibration of Sn‐Related Varshni Parameters for High Sn Content GeSn Layers

Bertrand, Mathieu; Thai, Q. M.; Chrétien, Jeremie; Pauc, N.; Aubin, J.; Milord, Laurent; Gassenq, A.; Hartmann, Jean‐Michel; Chelnokov, A.; Calvo, V.; Reboud, V.

doi:10.1002/andp.201800396

Cited by 18 publications

(15 citation statements)

References 34 publications

(36 reference statements)

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“…This contribution is assigned to light emission from the unstrained parts of the samples, located outside the 8 μm long waveguide, but inside the 12.5 μm pumping spot. This is in agreement with the expected emission from a relaxed GeSn 16% layer, as already shown in refs and at 25 K, indicating that recombination takes place in the highest Sn content layer. Note that the signal from the epilayer (referred to as “Blanket Layer” in Figure A) is slightly blue-shifted compared with the signal from the broken bridges (called “Relaxed” in Figure A), due to the slight residual compressive strain in the GeSn stack after epitaxy.…”

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confidence: 93%

GeSn Lasers Covering a Wide Wavelength Range Thanks to Uniaxial Tensile Strain

et al. 2019

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Silicon photonics continues to progress tremendously, both in near-infrared datacom/telecoms and in mid-IR optical sensing, despite the fact a monolithically integrated group IV semiconductor laser is still missing. GeSn alloys are one of the most promising candidate materials to realize such devices, as robust lasing under optical pumping was demonstrated by several groups up to mild cryogenic temperatures. Ideally, the integrated lasers should be tunable by design over a wide spectral range, offering a versatility that is required for optical sensing devices. We present here an innovative approach, taking advantage of local strain management in the semiconductor laser’s active zone. Arrays of differently strained Fabry-Pérot GeSn microlasers were fabricated side-by-side on the very same chip after blanket epitaxy on a Ge-buffered silicon-on-insulator substrate. Thanks to the local strain design, laser emission over a very large wavelength range under optical pumping, with laser lines peaking from 3.1 up to 4.6 μm at 25 K and with thresholds lower than 10 kW·cm–2. Laser operation persists up to 273 K, that is, very close to room temperature. This strategy, implemented on group IV semiconductors, opens up a new route to control the emission properties of microlasers integrated on a chip over significant photon energy windows representing a significant step forward in the integration and miniaturization of light sources emitting at a process-defined wavelength.

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confidence: 93%

GeSn Lasers Covering a Wide Wavelength Range Thanks to Uniaxial Tensile Strain

et al. 2019

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“…As we have achieved lasing for microdisks with Sn contents above 7%, we therefore assume that the microdisk emission stems from direct transitions. The experimental band gap dependence on Sn content shown in Figure b was thus fitted with E Γ ( x Sn ) by adjusting the bowing parameter and adopting b Γ = 2.77 eV, a value close to the 2.46 eV energy reported in ref . In previous reports, for instance in refs and where b Γ = 2.24 eV and b L = 0.89 eV were used, the indirect–direct band gap crossover was expected to occur at around 8% of Sn, as also reported in refs , , and − .…”

Section: Resultssupporting

confidence: 55%

“…The experimental band gap dependence on Sn content shown in Figure 2-b was thus fitted with E Γ (x Sn ) by adjusting the bowing parameter and adopting b Γ = 2.77 eV, a value close to the 2.46 eV energy reported in ref. 25 In previous reports, for instance in ref., 24,26 where b Γ = 2.24 eV and b L = 0.89 eV were used, the indirect-direct band gap crossover was expected to occur at around 8 % of Sn, as also reported in ref. 1,4,[27][28][29] Here, it occurred at 6.4 %, in good agreement with the modeled one for relaxed GeSn alloys.…”

Section: Optical Analysismentioning

confidence: 94%

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Reduced Lasing Thresholds in GeSn Microdisk Cavities with Defect Management of the Optically Active Region

et al. 2020

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GeSn alloys are nowadays considered as the most promising materials to build Group IV laser sources on silicon (Si) in a full complementary metal oxide semiconductorcompatible approach. Recent GeSn laser developments rely on increasing the band structure directness, by increasing the Sn content in thick GeSn layers grown on germanium (Ge) virtual substrates (VS) on Si. These lasers nonetheless suffer from a lack 1 of defect management and from high threshold densities. In this work we examine the lasing characteristics of GeSn alloys with Sn contents ranging from 7 % to 10.5 %. The GeSn layers were patterned into suspended microdisk cavities with different diameters in the 4-8 µm range. We evidence direct band gap in GeSn with 7 % of Sn and lasing at 2-2.3 µm wavelength under optical injection with reproducible lasing thresholds around 10 kW cm −2 , lower by one order of magnitude as compared to the literature. These results were obtained after the removal of the dense array of misfit dislocations in the active region of the GeSn microdisk cavities. The results offer new perspectives for future designs of GeSn-based laser sources.

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“…Here, we used b Γ = 2.46 eV and b L = 1.23 eV. 36 An exception to the Vegard's law was the Luttinger parameters γ 1 , γ 2 , and γ 3 , which were interpolated only within the alloy fraction range [0, 0.2]. All values inbetweens were interpolated using Vegard's law with x replaced by x/0.2.…”

Section: Methodsmentioning

confidence: 99%

A Light-Hole Quantum Well on Silicon

Assali¹,

Attiaoui²,

Vecchio³

et al. 2021

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The quiet quantum environment of holes in solid-state devices has been at the core of increasingly reliable architectures for quantum processors and memories. [1][2][3][4][5][6] However, due to the lack of scalable materials to properly tailor the valence band character and its energy offsets, the precise engineering of light-hole (LH) states remains a serious obstacle toward coherent photon-spin interfaces needed for a direct mapping of the quantum information encoded in photon flying qubits to stationary spin processor. [7][8][9] Herein, to alleviate this long-standing limitation we demonstrate an all-group IV low-dimensional system consisting of highly tensile strained germanium quantum well grown on silicon allowing new degrees of freedom to control and manipulate the hole states. Waferlevel, high bi-isotropic in-plane tensile strain (> 1%) is achieved using strain-engineered, metastable germanium-tin alloyed buffer layers yielding quantum wells with LH ground state, high g-factor anisotropy, and a tunable splitting of the hole subbands. The epitaxial heterostructures display sharp interfaces with sub-nanometer broadening and show room-temperature excitonic transitions that are modulated and extended to the mid-wave infrared by controlling strain and thickness. This ability to engineer quantum structures with LH selective confinement and controllable optical response enables manufacturable silicon-compatible platforms relevant to integrated quantum communication and sensing technologies.

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Experimental Calibration of Sn‐Related Varshni Parameters for High Sn Content GeSn Layers

Cited by 18 publications

References 34 publications

GeSn Lasers Covering a Wide Wavelength Range Thanks to Uniaxial Tensile Strain

GeSn Lasers Covering a Wide Wavelength Range Thanks to Uniaxial Tensile Strain

Reduced Lasing Thresholds in GeSn Microdisk Cavities with Defect Management of the Optically Active Region

A Light-Hole Quantum Well on Silicon

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