Coexistence of quantum-confined Stark effect and localized states in an (In,Ga)N/GaN nanowire heterostructure

Lähnemann, Jonas; Brandt, O.; Pfüller, Carsten; Flissikowski, Timur; Jahn, U.; Luna, E.; Hanke, Michael; Knelangen, M.; Trampert, A.; Grahn, H. T.

doi:10.1103/physrevb.84.155303

Cited by 43 publications

(74 citation statements)

References 37 publications

(62 reference statements)

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“…However, smaller blue-shifts were observed in the nanorod samples. These results indicate that the strain-induced QCSE still exists in the nanorods, in agreement with a recent study, 34 but the strain may be weaker in comparison to the parent MQWs.…”

Section: × 10supporting

confidence: 81%

Effects of reduced exciton diffusion in InGaN/GaN multiple quantum well nanorods

Jiang¹,

Zhang²,

Wang³

et al. 2012

Opt. Express

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Abstract：We observed different temperature-dependent behaviors of steady and transient emission properties in dry-etched InGaN/GaN multiple-quantum-well (MQW) nanorods and the parent MQWs. To clarify the impacts of nanofabrication on the emission properties, time-resolved photoluminescence spectra were recorded at various temperatures with carrier density in different regimes. The confinement of carrier transport was observed to play an important role to the emission properties in nanorods, inducing different temperature-dependent photoluminescence decay rates between the nanorods and MQWs. Moreover, together with other effects, such as surface damages and partial relaxation of the strain, the confinement effect causes faster recombination of carriers in nanorods.

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Section: × 10supporting

confidence: 81%

Effects of reduced exciton diffusion in InGaN/GaN multiple quantum well nanorods

Jiang¹,

Zhang²,

Wang³

et al. 2012

Opt. Express

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“…The specific sample under investigation was selected for the detailed analysis using luminescence spectroscopy by virtue of its high luminescence yield. In comparison to our previous study in [17], this sample contains thinner insertions separated by thicker barriers.…”

Section: Methodsmentioning

confidence: 79%

“…To attain the necessary control over the growth, a thorough understanding of the emission characteristics and the underlying physical processes is needed. To this end, micro-photoluminescence (µPL) spectroscopy on single NWs [15][16][17], but also spatially resolved cathodoluminescence (CL) spectroscopy [17][18][19], have been employed. Following these approaches, we use both CL spectral mapping in an SEM and µPL to investigate (In,Ga)N insertions in GaN NWs produced by a bottom-up approach.…”

Section: Introductionmentioning

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 resultingly different stoichiometry at the growth front may very well suppress the formation of nonradiative defects during the growth of the In x Ga 1−x N quantum discs. Second, In x Ga 1−x N disks in GaN NWs have been shown to exhibit large compositional fluctuations, 49,51,56 inducing carrier localization which in turn may at least partly prevent nonradiative recombination.…”

Section: Discussionmentioning

confidence: 99%

Comparison of the Luminous Efficiencies of Ga- and N-PolarInxGa1−xN/In
Fernández-Garrido
¹
,
Lähnemann
²
,
Hauswald
³

et al. 2016
Phys. Rev. Applied
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We investigate the luminescence of Ga-and N-polar In x Ga 1−x N/In y Ga 1−y N quantum wells grown by plasma-assisted molecular beam epitaxy on freestanding GaN as well as 6H-SiC substrates. In striking contrast to their Ga-polar counterparts, the N-polar quantum wells prepared on freestanding GaN do not exhibit any detectable photoluminescence even at 10 K. Theoretical simulations of the band profiles combined with resonant excitation of the quantum wells allow us to rule out carrier escape and subsequent surface recombination as the reason for this absence of luminescence. To explore the hypothesis of a high concentration of nonradiative defects at the interfaces between wells and barriers, we analyze the photoluminescence of Ga-and N-polar quantum wells prepared on 6H-SiC as a function of the well width. Intense luminescence is observed for both Ga-and N polar samples. As expected, the luminescence of the Ga-polar quantum wells quenches and red-shifts with increasing well width due to the quantum confined Stark effect. In contrast, both the intensity and the energy of the luminescence from the N-polar samples are essentially independent of well width. Transmission electron microscopy reveals that the N-polar quantum wells exhibit abrupt interfaces and homogeneous composition, excluding emission from In-rich clusters as the reason for this anomalous behavior. The microscopic origin of the luminescence in the N-polar samples is elucidated using spatially resolved cathodoluminescence spectroscopy. Regardless of well width, the luminescence is found to not originate from the N-polar quantum wells, but from the semipolar facets of ∨-pit defects. These results cast serious doubts on the potential of N-polar In x Ga 1−x N/In y Ga 1−y N quantum wells grown by plasma-assisted molecular beam epitaxy for the development of long-wavelength light emitting diodes. What remains to be seen is whether unconventional growth conditions may enable a significant reduction in the concentration of nonradiative defects.

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Coexistence of quantum-confined Stark effect and localized states in an (In,Ga)N/GaN nanowire heterostructure

Cited by 43 publications

References 37 publications

Effects of reduced exciton diffusion in InGaN/GaN multiple quantum well nanorods

Effects of reduced exciton diffusion in InGaN/GaN multiple quantum well nanorods

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

Comparison of the Luminous Efficiencies of Ga- and N-PolarInxGa1−xN/In
Fernández-Garrido
¹
,
Lähnemann
²
,
Hauswald
³

et al. 2016
Phys. Rev. Applied
Self Cite
17
1
14
0
View full text Add to dashboard Cite

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Coexistence of quantum-confined Stark effect and localized states in an (In,Ga)N/GaN nanowire heterostructure

Cited by 43 publications

References 37 publications

Effects of reduced exciton diffusion in InGaN/GaN multiple quantum well nanorods

Effects of reduced exciton diffusion in InGaN/GaN multiple quantum well nanorods

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

Comparison of the Luminous Efficiencies of Ga- and N-PolarInxGa1−xN/InFernández-Garrido1, Lähnemann2, Hauswald3 et al. 2016Phys. Rev. AppliedSelf Cite171140View full textAdd to dashboardCite

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Comparison of the Luminous Efficiencies of Ga- and N-PolarInxGa1−xN/In
Fernández-Garrido
¹
,
Lähnemann
²
,
Hauswald
³

et al. 2016
Phys. Rev. Applied
Self Cite
17
1
14
0
View full text Add to dashboard Cite