Disentangling the effects of nanoscale structural variations on the light emission wavelength of single nano-emitters: InGaN/GaN multiquantum well nano-LEDs for a case study

Sarau, George; Heilmann, Martin; Latzel, Michael; Christiansen, Silke

doi:10.1039/c4nr02939a

Cited by 25 publications

(33 citation statements)

References 46 publications

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“…S4, ESI †) as a result of the reduced quantum confined Stark effect (QCSE) due to strain relaxation in the MQWs. 9 Fig. 1(c) and (d) display PL images of the large nanorods using fluorescence lifetime imaging microscopy (FLIM), which demonstrates the high quality of the nanorod PL uniformity by simultaneously mapping the PL intensity (brightness) and lifetime (color).…”

Section: Resultsmentioning

confidence: 99%

“…Previously, researchers argued that these improvements were the result of a combination of in-plane strain relaxation, a decrease in the quantum-confined Stark effect (QCSE), light extraction efficiency enhancement and lateral carrier confinement. 6,[9][10][11] However, detailed analyses of carrier dynamics are still unable to explain the change in luminescence properties of MQW nanorods over planar layers with respect to their carrier density dependence. [12][13][14][15] In particular, the impact of the significant increase of surface states in nanorods is not fully understood.…”

Section: Introductionmentioning

confidence: 99%

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Free chargesversusexcitons: photoluminescence investigation of InGaN/GaN multiple quantum well nanorods and their planar counterparts

et al. 2018

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Free chargesversusexcitons: photoluminescence investigation of InGaN/GaN multiple quantum well nanorods and their planar counterparts

et al. 2018

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“…Figure 5 is showing a detailed view of three selected modes at different spectral positions with a small and large WGM shift at low and high energies, respectively, as already shown in figure 3(d). The blue dashed lines are the calculated TM 19,24,34 WGMs similar to figure 3(c). The new spectral positions of the WGMs for the green and red spectra obtained from sections 2 and 3, respectively, were also calculated.…”

Section: Determination Of the Carrier-concentration By Analysis Of Thmentioning

confidence: 96%

“…Two measurement configurations have been used for the micro-Raman investigations as illustrated in the inset of figure 4 [34]. In the − x z x ( , )¯configuration, i.e., laser excitation and detection is perpendicular to the microrod side-wall facet, the intense A 1 (TO) mode at ∼531.3 cm −1 covers the LOPPCM-peak.…”

Section: Determination Of the Carrier-concentration By Analysis Of Thmentioning

confidence: 99%

Carrier-induced refractive index change observed by a whispering gallery mode shift in GaN microrods

et al. 2015

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Vertical oriented GaN microrods were grown by metal-organic vapor phase epitaxy with four different n-type carrier concentration sections above 10 19 cm −3 along the c-axis. In cathodoluminescence investigations carried out on each section of the microrod, whispering gallery modes can be observed due to the hexagonal symmetry. Comparisons of the spectral positions of the modes from each section show the presence of an energy dependent mode shift, which suggest a carrier-induced refractive index change. The shift of the high energy edge of the near band edge emission points out that the band gap parameter in the analytical expression of the refractive index has to be modified. A proper adjustment of the band gap parameter explains the observed whispering gallery mode shift. ExperimentalThe GaN microrod samples were grown by a self-catalyzed vapor-liquid-solid (VLS) method on 2 inch c-plane sapphire substrates utilizing an Aixtron 200RF horizontal flow metal-organic vapor phase epitaxy (MOVPE) reactor [12]. Trimethylgallium (TMGa), silane, hydrogen, and ammonia were used as precursors. Silane is needed for n-type doping and enhances the vertical growth due to the formation of surface SiN acting as a

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“…In such cases, the sample has to be rotated by 90 • , see e.g. [6,22,23]. Rotating the sample is, however, sometimes infeasible or even impossible.…”

Section: Introductionmentioning

confidence: 99%

Towards polarization-based excitation tailoring for extended Raman spectroscopy

et al. 2020

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Undoubtedly, Raman spectroscopy is one of the most elaborated spectroscopy tools in materials science, chemistry, medicine and optics. However, when it comes to the analysis of nanostructured specimens, accessing the Raman spectra resulting from an exciting electric field component oriented perpendicularly to the substrate plane is a difficult task and conventionally can only be achieved by mechanically tilting the sample, or by sophisticated sample preparation. Here, we propose a novel experimental method based on the utilization of polarization tailored light for Raman spectroscopy of individual nanostructures. As a proof of principle, we create three-dimensional electromagnetic field distributions at the nanoscale using tightly focused cylindrical vector beams impinging normally onto the specimen, hence keeping the conventional beam-path of commercial Raman systems. Using this excitation scheme, we experimentally show that the recorded Raman spectra of individual gallium-nitride nanostructures of sub-wavelength diameter used as a test platform depend sensitively on their location relative to the focal vector field. The arXiv:1905.12325v1 [physics.optics] 29 May 2019 observed Raman spectra can be attributed to the interaction with transverse or longitudinal electric field components. This novel technique may pave the way towards a characterization of Raman active nanosystems using full information of all Raman modes.

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Disentangling the effects of nanoscale structural variations on the light emission wavelength of single nano-emitters: InGaN/GaN multiquantum well nano-LEDs for a case study

Cited by 25 publications

References 46 publications

Free chargesversusexcitons: photoluminescence investigation of InGaN/GaN multiple quantum well nanorods and their planar counterparts

Free chargesversusexcitons: photoluminescence investigation of InGaN/GaN multiple quantum well nanorods and their planar counterparts

Carrier-induced refractive index change observed by a whispering gallery mode shift in GaN microrods

Towards polarization-based excitation tailoring for extended Raman spectroscopy

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