Effect of interface grading and lateral thickness variation on x-ray diffraction by InGaN/GaN multiple quantum wells

Lee, S.R.; Koleske, Daniel; Crawford, Mary H.; Wierer, Jonathan J.

doi:10.1016/j.jcrysgro.2012.06.048

Cited by 15 publications

(9 citation statements)

References 67 publications

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“…For each structure the fits are made under the assumption of full coherency strain of the InGaN and AlGaN layers to the underlying GaN lattice, discrete changes in alloy concentrations, and no compositional grading of the interfaces. The influence of compositional grades at the top InGaN/GaN interface has been described by Lee et al and leads to diminishing peak intensity for higher order superlattice peaks [29]. The IL aluminum concentrations and thicknesses were determined separately using XRD analysis of the same MQW growth run without TMIn flowing during the MQW growth.…”

Section: Methodsmentioning

confidence: 99%

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On the increased efficiency in InGaN-based multiple quantum wells emitting at 530–590 nm with AlGaN interlayers

Koleske

Fischer

Bryant

et al. 2015

Journal of Crystal Growth

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InGaN/AlGaN/GaN-based multiple quantum wells (MQWs) with AlGaN interlayers (ILs) are investigated, specifically to examine the fundamental mechanisms behind their increased radiative efficiency at wavelengths of 530-590 nm. The Al z Ga 1-z N (z ~ 0.38) IL is ~1-2 nm thick, and is grown after and at the same growth temperature as the ~3 nm thick InGaN quantum well (QW). This is followed by an increase in temperature for the growth of a ~10 nm thick GaN barrier layer. The insertion of the AlGaN IL within the MQW provides various benefits. First, the AlGaN IL allows for growth of the In x Ga 1-x N QW well below typical growth temperatures to achieve higher x (up to ~ 0.25). Second, annealing the IL capped QW prior to the GaN barrier growth improves the AlGaN IL smoothness as determined by atomic force microscopy, improves the InGaN/AlGaN/GaN interface quality as determined from scanning transmission electron microscope images and x-ray diffraction, and increases the radiative efficiency by reducing non-radiative defects as determined by time-resolved photoluminescence measurements. Finally, the AlGaN IL increases the spontaneous and piezoelectric polarization induced electric fields acting on the InGaN QW, providing an additional red-shift to the emission wavelength as determined by Schrodinger-Poisson modeling and fitting to the experimental data. The relative impact of increased indium concentration and polarization fields on the radiative efficiency of MQWs with AlGaN ILs is explored along with implications to conventional longer wavelength emitters.

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Section: Methodsmentioning

confidence: 99%

“…1 2.0 nm. The top interface roughness is likely the result of multiple step height formation [11] and/or increased indium compositional grading [29].…”

Section: Increase In Emission Wavelength With Indium Composition Withmentioning

confidence: 99%

On the increased efficiency in InGaN-based multiple quantum wells emitting at 530–590 nm with AlGaN interlayers

Koleske

Fischer

Bryant

et al. 2015

Journal of Crystal Growth

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“…Additionally, QWs formed from InGaN are much thinner than those formed in other semiconductor systems, and have relatively high interface roughness (∆L ∼ 0.6-1.5 nm). [43][44][45] The Auger coefficient (C Auger ) is plotted as a function of interface roughness (Fig. 3a) and ratio of interface roughness (Fig.…”

Section: Auger Recombination Rates In Iii-nitride Quantum Wells Wmentioning

confidence: 99%

“…39,40 Specifically, for GaAs QWs with AlGaAs energy barrier layers the interface roughness is one to two monolayers (3-5 Å), 41 for InGaAs/InP QW/barriers it is one to four monolayers, 42 and InGaN/GaN QW/barriers it is one to six monolayers (3-18 Å). [43][44][45] The variation in the InGaN QW is notable because it is considerably large when compared to the typical quantum well thickness (L QW ) that is in the range of 2-3 nm. Clearly, interface roughness is a feature of all semiconductor QWs, and the role of interface roughness has been discussed for the photoluminescence line shape analysis for QW.…”

Section: Introductionmentioning

confidence: 99%

Effect of interface roughness on Auger recombination in semiconductor quantum wells

et al. 2017

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Auger recombination in a semiconductor is a three-carrier process, wherein the energy from the recombination of an electron and hole pair promotes a third carrier to a higher energy state. In semiconductor quantum wells with increased carrier densities, the Auger recombination becomes an appreciable fraction of the total recombination rate and degrades luminescence efficiency. Gaining insight into the variables that influence Auger recombination in semiconductor quantum wells could lead to further advances in optoelectronic and electronic devices. Here we demonstrate the important role that interface roughness has on Auger recombination within quantum wells. Our computational studies find that as the ratio of interface roughness to quantum well thickness is increased, Auger recombination is significantly enhanced. Specifically, when considering a realistic interface roughness for an InGaN quantum well, the enhancement in Auger recombination rate over a quantum well with perfect heterointerfaces can be approximately four orders of magnitude.

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“…23 Thus, the HRXRD models refined by APT profiles represent an improvement in the analysis of continuous QWs. The trapezoid model by Lee et al 30 is an intermediate approach that also improves fitting compared to the assumption of rectangular quantum wells.…”

Section: -2mentioning

confidence: 99%

Correlated high-resolution x-ray diffraction, photoluminescence, and atom probe tomography analysis of continuous and discontinuous InxGa1−xN quantum wells

Ren

Riley

Koleske

et al. 2015

Applied Physics Letters

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Effect of interface grading and lateral thickness variation on x-ray diffraction by InGaN/GaN multiple quantum wells

Cited by 15 publications

References 67 publications

On the increased efficiency in InGaN-based multiple quantum wells emitting at 530–590 nm with AlGaN interlayers

On the increased efficiency in InGaN-based multiple quantum wells emitting at 530–590 nm with AlGaN interlayers

Effect of interface roughness on Auger recombination in semiconductor quantum wells

Correlated high-resolution x-ray diffraction, photoluminescence, and atom probe tomography analysis of continuous and discontinuous InxGa1−xN quantum wells

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