Low‐strain, quantum‐cascade‐laser active regions grown on metamorphic buffer layers for emission in the 3.0–4.0 μm wavelength region

Mawst, Luke J.; Kirch, Jeremy; Kim, Tae‐Wan; Garrod, T.; Boyle, Colin; Botez, D.; Zutter, Brian; Schulte, Kevin L.; Kuech, T. F.; Bouzi, Pierre M.; Gmachl, Claire F.; Earles, T.

doi:10.1049/iet-opt.2013.0060

Cited by 8 publications

(9 citation statements)

References 36 publications

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“…In x Ga 1 À x As metamorphic buffer layers (MBLs) with tunable lattice constants can be used in device applications where a lattice parameter between GaAs and InP or between InP and InAs is desired. Recently they have garnered interest as a potential route to low strain mid-IR laser devices emitting in the 3.0-4.0 μm range [3,4]. Growth of these devices is quite sensitive to the orientation of the substrate surface.…”

Section: Introductionmentioning

confidence: 99%

Evolution of epilayer tilt in thick In Ga1−As metamorphic buffer layers grown by hydride vapor phase epitaxy

Schulte

Strand

Kuech

2015

Journal of Crystal Growth

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a b s t r a c tTilt behavior in thick In x Ga 1 À x As metamorphic buffer layers (MBLs) grown by hydride vapor phase epitaxy (HVPE) was measured by high-resolution reciprocal space mapping.Step-graded and continuously-graded structures, grown on nominally (001) oriented GaAs substrates, were analyzed. Tilt was measured as a function of position in a step-graded MBL. It was found that the tilt was strongest near the edges and tended to point toward the sample center.Step-grading induced a nearly linear tilt increase with x InAs , while tilt increased slowly below x InAs $ 0.10 then increased more sharply with In concentration in continuously-graded samples. The tilt behavior could be described by a model in which the tilt is attributed to imbalances in dislocations that result from cross-slip within a glide length of the sample edge. This finding implies that dislocation multiplication by cross slip is an important strain relief mechanism during the growth of these MBLs. Strategies for minimizing tilt in HVPE MBLs are discussed.

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Section: Introductionmentioning

confidence: 99%

Evolution of epilayer tilt in thick In Ga1−As metamorphic buffer layers grown by hydride vapor phase epitaxy

Schulte

Strand

Kuech

2015

Journal of Crystal Growth

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“…This change in lattice parameter allows for the use of barrier and well compositions which would be otherwise prohibited due to excessive strain if grown on a conventional substrate, thus enables the development of a short-emission-wavelength QCL of potentially significantly improved performance [2,7]. CMP and wet-chemical etching is found to be effective in preparing the MBL surface for growth of the QCL structure.…”

Section: Discussionmentioning

confidence: 99%

“…The MBLs were characterized using high-resolution X-ray diffraction (HR-XRD) and reciprocal space mapping (RSM). The MBL cap is found to be nearly fully relaxed (495%) owing to the thickness and can exhibit a crystallographic tilt with respect to the substrate, which is a function of composition and thickness [2,4].…”

Section: Methodsmentioning

confidence: 99%

“…Metamorphic buffer layers (MBLs) can serve as a "virtual substrate" with a designer-chosen surface lattice constant, thus expanding the compositional-design space for a variety of device structures, including short-wavelength ( o3.5 μm) Quantum Cascade Lasers (QCLs) [1,2]. However, the strain relaxation, which occurs within the MBL, gives rise to a rough cross-hatched surface morphology [3,4] which may impact subsequently grown device structures.…”

Section: Introductionmentioning

confidence: 99%

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Regrowth of quantum cascade laser active regions on metamorphic buffer layers

Rajeev

Mawst

Kirch

et al. 2016

Journal of Crystal Growth

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Communicated by T. PaskovaKeywords: A3. Superlattice B3. Quantum cascade lasers A3. Metalorganic vapor phase epitaxy B2. Semiconducting III-V materials a b s t r a c t Metamorphic buffer layers (MBLs) were used as substrates with lattice constants selected for designing and fabricating intersubband transition sources involving strained superlattices (SLs) such as Quantum Cascade Lasers (QCLs). Chemical mechanical planarization (CMP) was used to prepare the InGaAs-based MBLs for epitaxial growth. Indium enrichment of the InGaAs layer on the MBL surfaces was observed when annealed at the regrowth temperatures. This post-anneal enhancement was eliminated by including a wet-etch treatment after CMP, which results in an epi-ready surface for regrowth. Ten stages of a QCL core region structure, designed for emission at a 3.4 μm wavelength are regrown on a surfaceoptimized MBL. Such structures exhibit well defined X-ray diffraction pendellösung fringes, and transmission electron microscopy confirms planar superlattice interfaces with layer thicknesses that are in good agreement with the design target.

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“…19,20 These "virtual substrates" under consideration were grown on (001) GaAs substrates by hydride vapor phase epitaxy. 21 They consisted of nine In x Ga 1−x As layers with linear grading of the In content in each of the nine ∼1.0-μm-thick steps. The final layer was a constant-composition cap layer which is typically ∼15-μm thick to allow for surface preparation in order to perform the regrowth of strained layers atop with high fidelity.…”

Section: Introductionmentioning

confidence: 99%

Design considerations for λ ∼ 3.0- to 3.5-μm-emitting quantum cascade lasers on metamorphic buffer layers

et al. 2017

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Design considerations for λ ∼ 3.0-to 3.5-μm-emitting quantum cascade lasers on metamorphic buffer layers," Opt. Eng.Abstract. Quantum cascade lasers (QCLs) that employ metamorphic buffer layers as substrates of variable lattice constant have been designed for emission in the 3.0-to 3.5-μm wavelength range. Theoretical analysis of the active-region (AR) energy band structure, while using an 8-band k • p model, reveals that one can achieve both effective carrier-leakage suppression as well as fast carrier extraction in QCL structures of relatively low strain. Significantly lower indium-content quantum wells (QWs) can be employed for the AR compared to QWs employed for conventional short-wavelength QCL structures grown on InP, which, in turn, is expected to eliminate carrier leakage to indirect-gap valleys (X, L). An analysis of thermo-optical characteristics for the complete device design indicates that high-Al-content AlInAs cladding layers are more effective for both optical confinement and thermal dissipation than InGaP cladding layers. An electroluminescence-spectrum full-width half-maximum linewidth of 54.6 meV is estimated from interface roughness scattering and, by considering both inelastic and elastic scattering, the threshold-current density for 3.39-μm-emitting, 3-mm-long back-facet-coated QCLs is projected to be 1.40 kA∕cm 2 .

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Low‐strain, quantum‐cascade‐laser active regions grown on metamorphic buffer layers for emission in the 3.0–4.0 μm wavelength region

Cited by 8 publications

References 36 publications

Evolution of epilayer tilt in thick In Ga1−As metamorphic buffer layers grown by hydride vapor phase epitaxy

Evolution of epilayer tilt in thick In Ga1−As metamorphic buffer layers grown by hydride vapor phase epitaxy

Regrowth of quantum cascade laser active regions on metamorphic buffer layers

Design considerations for λ ∼ 3.0- to 3.5-μm-emitting quantum cascade lasers on metamorphic buffer layers

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