The critical thickness of InGaN on (0001)GaN

Leyer, Martin; Stellmach, Joachim; Meißner, Ch.; Pristovsek, Markus; Kneissl, Michael

doi:10.1016/j.jcrysgro.2008.08.021

Cited by 109 publications

(59 citation statements)

References 11 publications

(14 reference statements)

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“…Contrary to previous reports on MOVPE-grown epilayers, 28,30,32,[37][38][39][40] in our case (PAMBE), the sequestration phenomenon was not correlated to 3D growth. Hence, we do not support the argument that this phenomenon is a manifestation of a StranskiKrastanow growth mode.…”

Section: Discussioncontrasting

confidence: 99%

“…[37][38][39][40] The sequestration phenomenon has also been observed in PAMBE-grown epilayers, but the relevant reports in films grown by this method are very sparse. 21,41 Based on the afore-given literature review, there is no consensus on what actually takes place during the relaxation of InGaN films, i.e., if there is a strain or compositional discontinuity (or both) close to the InGaN/GaN interface or whether chemical and strain gradients are in place.…”

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confidence: 99%

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Defects, strain relaxation, and compositional grading in high indium content InGaN epilayers grown by molecular beam epitaxy

Bazioti

Papadomanolaki

Kehagias

et al. 2015

Journal of Applied Physics

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Articles you may be interested inStructural anisotropic properties of a-plane GaN epilayers grown on r-plane sapphire by molecular beam epitaxy J. Appl. Phys. 115, 213506 (2014) We investigate the structural properties of a series of high alloy content InGaN epilayers grown by plasma-assisted molecular beam epitaxy, employing the deposition temperature as variable under invariant element fluxes. Using transmission electron microscopy methods, distinct strain relaxation modes were observed, depending on the indium content attained through temperature adjustment. At lower indium contents, strain relaxation by V-pit formation dominated, with concurrent formation of an indium-rich interfacial zone. With increasing indium content, this mechanism was gradually substituted by the introduction of a self-formed strained interfacial InGaN layer of lower indium content, as well as multiple intrinsic basal stacking faults and threading dislocations in the rest of the film. We show that this interfacial layer is not chemically abrupt and that major plastic strain relaxation through defect introduction commences upon reaching a critical indium concentration as a result of compositional pulling. Upon further increase of the indium content, this relaxation mode was again gradually succeeded by the increase in the density of misfit dislocations at the InGaN/GaN interface, leading eventually to the suppression of the strained InGaN layer and basal stacking faults. V C 2015 AIP Publishing LLC. [http://dx

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Section: Discussioncontrasting

confidence: 99%

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confidence: 99%

Defects, strain relaxation, and compositional grading in high indium content InGaN epilayers grown by molecular beam epitaxy

Bazioti

Papadomanolaki

Kehagias

et al. 2015

Journal of Applied Physics

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“…When the effective thickness of the lattice-mismatched MQW active region is beyond its critical layer thickness [22], the misfit strain relaxation accompanied with the generation of defects takes place during the epitaxial growth. The strain relaxation is most likely to take place for the 11-QW LED device according to other reports [23][24][25]. Thus considerable defects generated in the relaxation process lead to the significant SRH nonradiative recombination.…”

Section: Resultsmentioning

confidence: 78%

Nonradiative recombination — critical in choosing quantum well number for InGaN/GaN light-emitting diodes

Zhang¹,

Zhang²,

Liu³

et al. 2014

Opt. Express

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Abstract:In this work, InGaN/GaN light-emitting diodes (LEDs) possessing varied quantum well (QW) numbers were systematically investigated both numerically and experimentally. The numerical computations show that with the increased QW number, a reduced electron leakage can be achieved and hence the efficiency droop can be reduced when a constant Shockley-Read-Hall (SRH) nonradiative recombination lifetime is used for all the samples. However, the experimental results indicate that, though the efficiency droop is suppressed, the LED optical power is first improved and then degraded with the increasing QW number. The analysis of the measured external quantum efficiency (EQE) with the increasing current revealed that an increasingly dominant SRH nonradiative recombination is induced with more epitaxial QWs, which can be related to the defect generation due to the strain relaxation, especially when the effective thickness exceeds the critical thickness. These observations were further supported by the carrier lifetime measurement using a pico-second time-resolved photoluminescence (TRPL) system, which allowed for a revised numerical modeling with the different SRH lifetimes considered. This work provides useful guidelines on choosing the critical QW number when designing LED structures.

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“…This effect of surface roughening is generated by the 3-dimensional growth mode with strain relaxation, because the thickness exceeds the critical thickness of InGaN alloy. [11] With increasing In composition of the InGaN layer, the surface smoothness was the In 0.3 Ga 0.7 N layer, despite only 4 nm thickness (Fig. 2(c)).…”

Section: Resultsmentioning

confidence: 91%

Influence of Quantum well Thickness Fluctuation on Optical Properties of InGaN/GaN Multi Quantum well Structure Grown by PA-MBE

Woo

Kim

Cho

et al. 2017

Appl. Sci. Converg. Technol.

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An InGaN/GaN multiple quantum well (MQW) structure is grown on a GaN/sapphire template using a plasma-assisted molecular beam epitaxy (PA-MBE). The fluctuation of the quantum well thickness formed from roughly-grown InGaN layer results in a disordered photoluminescence (PL) spectrum. The surface morphologies of the InGaN layers with various In compositions are investigated by reflection high energy electron diffraction (RHEED) and atomic force microscopy (AFM). A blurred InGaN/GaN hetero-interface and the non-uniform QW size is confirmed by high resolution transmission electron microscopy (HR-TEM). Inhomogeneity of the quantum confinement results in a degradation of the quantum efficiency even though the InGaN layer has a uniform In composition.

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The critical thickness of InGaN on (0001)GaN

Cited by 109 publications

References 11 publications

Defects, strain relaxation, and compositional grading in high indium content InGaN epilayers grown by molecular beam epitaxy

Defects, strain relaxation, and compositional grading in high indium content InGaN epilayers grown by molecular beam epitaxy

Nonradiative recombination — critical in choosing quantum well number for InGaN/GaN light-emitting diodes

Influence of Quantum well Thickness Fluctuation on Optical Properties of InGaN/GaN Multi Quantum well Structure Grown by PA-MBE

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