Sensitivity of heterointerfaces on emission wavelength of quantum cascade lasers

Wang, C.A.; Schwarz, Benedikt; Siriani, Dominic F.; Connors, M.K.; Missaggia, L.J.; Calawa, D.R.; McNulty, Daniel; Akey, Austin; Mei, Zhigang; Donnelly, J.P.; Mansuripur, Tobias S.; Capasso, Federico

doi:10.1016/j.jcrysgro.2016.11.029

Cited by 19 publications

(21 citation statements)

References 28 publications

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“…Lattice-matched InAlAs/InGaAs QCL active regions grown by molecular beam epitaxy (MBE) also exhibit four monolayers of compositional grading in the interfaces [10]. Indium segregation was not indicated at any interfaces in either of the SLs studied here, unlike what was reported in Ref [2].…”

Section: Extent Of Interfacial Mixing In the Thin-motif Samplecontrasting

confidence: 49%

“…The veracity of the asymmetry could be tested by running the atom probe experiments from the substrate down, in the opposite direction to that used in this study, but such experiments have not yet been achieved. Asymmetric graded interfaces (2.5-4.5 nm in width) have also been observed for lattice-matched InAlAs/InGaAs SL structures grown by OMVPE [2], and for InGaAsP multiple quantum well (MQW) structures where Ga and As are diffused asymmetrically into the lower and upper InP buffer layers [14], as well as for InGaN/GaN quantum wells where the upper InGaN/GaN interface is found to be 1.3 nm wide and the lower interface is 0.6 nm wide, in that study [15]. Lattice-matched InAlAs/InGaAs QCL active regions grown by molecular beam epitaxy (MBE) also exhibit four monolayers of compositional grading in the interfaces [10].…”

Section: Extent Of Interfacial Mixing In the Thin-motif Samplementioning

confidence: 71%

“…Profiles of the In, Al, and Ga concentrations in the growth direction elucidate the compositional sharpness of the interfaces in two strained-layer SLs. Prior studies of this type on a nominally lattice-matched SL explained the red-shifted emission wavelength for QCLs on InP [2].…”

Section: Introductionmentioning

confidence: 96%

“…A desirable feature of QCLs, being intersubband transition devices, is the tunability of the emission wavelength through the design of the thickness and composition of each layer within a chosen material system. However, these structures are sensitive to small deviations from the designed thicknesses and compositions, which can alter the emission wavelength through changes in the electron wavefunctions in the conduction band [2]. Moreover, for strain-compensated superlattices (SLs), minor thickness variations can lead to an imbalance in the overall strain-thickness product, which may result in strain relaxation in the several-microns-thick active region.…”

Section: Introductionmentioning

confidence: 99%

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Interfacial Mixing Analysis for Strained Layer Superlattices by Atom Probe Tomography

et al. 2018

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Quantum wells and barriers with precise thicknesses and abrupt composition changes at their interfaces are critical for obtaining the desired emission wavelength from quantum cascade laser devices. High-resolution X-ray diffraction and transmission electron microscopy are commonly used to calibrate and characterize the layers’ thicknesses and compositions. A complementary technique, atom probe tomography, was employed here to obtain a direct measurement of the 3-dimensional spatially-resolved compositional profile in two InxGa1−xAs/InyAl1−yAs III-V strained-layer superlattice structures, both grown at 605 °C. Fitting the measured composition profiles to solutions to Fick’s Second Law yielded an average interdiffusion coefficient of 3.5 × 10−23 m2 s−1 at 605 °C. The extent of interdiffusion into each layer determined for these specific superlattices was 0.55 nm on average. The results suggest that quaternary active layers will form, rather than the intended ternary compounds, in structures with thicknesses and growth protocols that are typically designed for quantum cascade laser devices.

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Section: Extent Of Interfacial Mixing In the Thin-motif Samplecontrasting

confidence: 49%

Section: Extent Of Interfacial Mixing In the Thin-motif Samplementioning

confidence: 71%

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

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Interfacial Mixing Analysis for Strained Layer Superlattices by Atom Probe Tomography

et al. 2018

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“…Microdefects in InAlAs/InP described in the literature were reported to depend strongly on the growth conditions, with a rather narrow range of technological parameters of microdefects-free growth [9,12,17] around 500 °C, also with improved InAlAs properties at much higher temperatures around 600 °C [18] or around 650-750°C used in MOVPE [19]. During the growth of test structures, the optical reflectometry signal was collected in real time, similarly as described above for QCL growth.…”

Section: Background Of the Problemmentioning

confidence: 99%

Optimization of MBE Growth Conditions of In0.52Al0.48As Waveguide Layers for InGaAs/InAlAs/InP Quantum Cascade Lasers

Gutowski

Sankowska

Słupiński

et al. 2019

Preprint

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We investigate molecular beam epitaxy growth conditions of micrometers-thick In0.52Al0.48As designed for waveguide of InGaAs/InAlAs/InP quantum cascade lasers. Effect of growth temperature and V/III ratio on the surface morphology and defect structure were studied. The growth conditions which were developed for the growth of cascaded In0.53Ga0.47As/In0.52Al0.48As active region, e.g. growth temperature of TG=520°C and V/III ratio of 12, turned out to be not optimum for the growth of thick In0.52Al0.48As waveguide layers. It has been observed that after exceeding ~1µm thickness the quality of In0.52Al0.48As layers deteriorates. The in-situ optical reflectometry showed increasing surface roughness caused by defect forming, which was further confirmed by High Resolution X-Ray reciprocal space mapping, optical microscopy and atomic force microscopy. The presented optimization of growth conditions of In0.52Al0.48As waveguide layer led to the growth of defect free material, with good optical quality. This has been achieved by decreasing the growth temperature to TG=480 °C with appropriate increasing V/III ratio. At the same time the growth conditions of the cascade active region of the laser were left unchanged. The lasers grown using new recipe have shown lower threshold currents and improved slope efficiency. We relate this performance improvement to reduction of the electron scattering on the interface roughness and decreased waveguide absorption losses.

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Interfacial characteristics dependence on interruption times in InGaAs/InAlAs superlattice grown by molecular beam epitaxy

Lee,

Seo,

Shin

et al. 2024

Journal of Alloys and Compounds

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Sensitivity of heterointerfaces on emission wavelength of quantum cascade lasers

Cited by 19 publications

References 28 publications

Interfacial Mixing Analysis for Strained Layer Superlattices by Atom Probe Tomography

Interfacial Mixing Analysis for Strained Layer Superlattices by Atom Probe Tomography

Optimization of MBE Growth Conditions of In0.52Al0.48As Waveguide Layers for InGaAs/InAlAs/InP Quantum Cascade Lasers

Interfacial characteristics dependence on interruption times in InGaAs/InAlAs superlattice grown by molecular beam epitaxy

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