Misorientation defects in coalesced self-catalyzed GaN nanowires

Grossklaus, Kevin A.; Banerjee, Animesh; Jahangir, Shafat; Bhattacharya, P.; Millunchick, Joanna Mirecki

doi:10.1016/j.jcrysgro.2013.02.019

Cited by 46 publications

(44 citation statements)

References 17 publications

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“…However, plastic relaxation at the joints may also induce the creation of large-angle boundaries between coalesced nanowire segments. The xray diffraction profiles studied in the present work are insensitive to the microstructure of the joints because of their small volume, and the available microcopic studies in the literature [19][20][21][22] do not clarify this question either. Clearly, dedicated microscopic studies are needed to reveal the actual microstructure of the joints.…”

Section: Discussionmentioning

confidence: 70%

“…The elastic energy of such a dense dislocation array may be reduced further by building a large-angle boundary with a coincidence site lattice at the interface. Transmission electron microscopy studies of GaN nanowires reveal dislocations at the coalescence joints [19,20,22] and also "zipper" defects [21] whose atomic structure remains obscure. Hence, further microscopic studies are needed to understand the relaxation at the nanowire joints in more detail.…”

Section: Energetics Of Plastic Relaxationmentioning

confidence: 99%

“…Dislocations at the joints [19][20][21][22] form small angle boundaries and reduce the curvature of the nanowires. Since these dislocations run across the nanowires, the strain relaxation at the free side surface restricts the range of their elastic fields to distances comparable with the nanowire diameters.…”

Section: Introductionmentioning

confidence: 99%

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Elastic versus Plastic Strain Relaxation in Coalesced GaN Nanowires: An X-Ray Diffraction Study

2016

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The coalescence in dense arrays of spontaneously formed GaN nanowires proceeds by bundling: adjacent nanowires bend and merge at their top, thus reducing their surface energy at the expense of the elastic energy of bending. We give a theoretical description of the energetics of this bundling process. The bending energy is shown to be substantially reduced by the creation of dislocations at the coalescence joints. A comparison of experimental and calculated x-ray diffraction profiles from ensembles of bundled nanowires demonstrates that a large part of the bending energy is indeed relaxed by plastic deformation. The residual bending manifests itself by extended tails of the diffraction profiles.

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Section: Discussionmentioning

confidence: 70%

Section: Energetics Of Plastic Relaxationmentioning

confidence: 99%

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Elastic versus Plastic Strain Relaxation in Coalesced GaN Nanowires: An X-Ray Diffraction Study

2016

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“…Indeed, dislocation densities are significantly reduced compared to planar heteroepitaxy [28,29], and also the emission related to native point defects might be less significant [30]. However, already the coalescence of neighboring NWs in dense arrays might introduce stacking faults and dislocations [31,32]. Furthermore, reduced growth temperatures are required for the incorporation of In.…”

Section: Spatially and Spectrally Resolved Emission Within Single Nwsmentioning

confidence: 99%

Localization and defects in axial (In,Ga)N/GaN nanowire heterostructures investigated by spatially resolved luminescence spectroscopy

Lähnemann¹,

Hauswald²,

Wölz³

et al. 2014

J. Phys. D: Appl. Phys.

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Abstract. (In,Ga)N insertions embedded in self-assembled GaN nanowires are of current interest for applications in solid-state light emitters. Such structures exhibit a notoriously broad emission band. We use cathodoluminescence spectral imaging in a scanning electron microscope and micro-photoluminescence spectroscopy on single nanowires to learn more about the mechanisms underlying this emission. We observe a shift of the emission energy along the stack of six insertions within single nanowires that may be explained by compositional pulling. Our results also corroborate reports that the localization of carriers at potential fluctuations within the insertions plays a crucial role for the luminescence of these nanowire based emitters. Furthermore, we resolve contributions from both structural and point defects in our measurements.

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“…The low values of g i and the non-radiative lifetime are attributed to defects in the nanowire and disk regions. Extended defects can be caused by coalescing of nanowires during epitaxy 21 either due to misorientation or due to increasing nanowire diameter at the low temperature of epitaxy. These defects behave electronically as nonradiative deep levels.…”

Section: à2mentioning

confidence: 99%

III-nitride disk-in-nanowire 1.2 μm monolithic diode laser on (001)silicon

Hazari

Aiello

et al. 2015

Applied Physics Letters

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III-nitride nanowire diode heterostructures with multiple In0.85Ga0.15N disks and graded InGaN mode confining regions were grown by molecular beam epitaxy on (001)Si substrates. The aerial density of the 60 nm nanowires is ∼3 × 1010 cm−2. A radiative recombination lifetime of 1.84 ns in the disks is measured by time-resolved luminescence measurements. Edge-emitting nanowire lasers have been fabricated and characterized. Measured values of Jth, T0, and dg/dn in these devices are 1.24 kA/cm2, 242 K, and 5.6 × 10−17 cm2, respectively. The peak emission is observed at ∼1.2 μm.

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Misorientation defects in coalesced self-catalyzed GaN nanowires

Cited by 46 publications

References 17 publications

Elastic versus Plastic Strain Relaxation in Coalesced GaN Nanowires: An X-Ray Diffraction Study

Elastic versus Plastic Strain Relaxation in Coalesced GaN Nanowires: An X-Ray Diffraction Study

Localization and defects in axial (In,Ga)N/GaN nanowire heterostructures investigated by spatially resolved luminescence spectroscopy

III-nitride disk-in-nanowire 1.2 μm monolithic diode laser on (001)silicon

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