Luminescence properties of isolated InGaN/GaN quantum dots

Martin, Robert; Edwards, P. R.; Taylor, Robert A.; Rice, James H.; Na, J. H.; Robinson, James W.; Smith, Jonathan; Liu, C.; Watson, I. M.

doi:10.1002/pssa.200460307

Cited by 24 publications

(22 citation statements)

References 12 publications

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“…1,2 Self-assembly is the spontaneous and reversible organization of particulate units (e.g., molecules or nanoparticles) into higher ordered structures, 8,9 which has been applied to produce a wide range of materials with nanometer sized features such as one dimensional quantum wires or zero dimensional quantum dots. [10][11][12][13][14] One application of self-assembly is to make precisely patterned materials that possess well defined properties by organising particles with specific physical properties via external directing (e.g., electric) fields. 15 Ferroelectric lithography is an approach based on patterning the spontaneous polarization inside ferroelectric crystals so as to engineer static electric field distributions, suitable for driving bottom-up assembly and nanodeposition at the surface of ferroelectric templates.…”

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confidence: 99%

Surface enhanced luminescence and Raman scattering from ferroelectrically defined Ag nanopatterned arrays

et al. 2013

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confidence: 99%

Surface enhanced luminescence and Raman scattering from ferroelectrically defined Ag nanopatterned arrays

et al. 2013

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“…Plasmon active arrays possessing regularly positioned plasmon active sites provide a geometry design that supports a homogenous signal enhancement across a large sample surface area. Modern nanofabrication methodologies enable the creation of a number of different nanostructures with precisely controlled shapes, sizes, and spacing [3][4][5][6][7][8][9][10]. This has extended to the creation of a range of different metallic nanostructures array designs that produce localized surface plasmon resonances (LSPRs) [8][9][10][11][12][13][14][15].…”

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confidence: 99%

Plasmon enhanced fluorescence studies from aligned gold nanorod arrays modified with SiO2 spacer layers

Damm

Fedele

Murphy

et al. 2015

Applied Physics Letters

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Here, we demonstrate that quasi self-standing Au nanorod arrays prepared with plasma polymerisation deposited SiO2 dielectric spacers support surface enhanced fluorescence (SEF) while maintaining high signal reproducibility. We show that it is possible to find a balance between enhanced radiative and non-radiative decay rates at which the fluorescent intensity is maximized. The SEF signal optimised with a 30 nm spacer layer thickness showed a 3.5-fold enhancement with a signal variance of <15% thereby keeping the integrity of the nanorod array. We also demonstrate the decreased importance of obtaining resonance conditions when localized surface plasmon resonance is positioned within the spectral region of Au interband transitions. Procedures for further increasing the SEF enhancement factor are also discussed.

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“…Hence we assign peak X to the single exciton emission, and peak XX to the biexciton-to-exciton transition. 22,23 The large negative binding energies of XX (> 10 meV) are commonly observed in III-N QDs [24][25][26][27][28][29][30][31] . It is due to the residual strain, even in dots with such small sizes, which enhances the repulsive excitonexciton Coulomb interaction 26 .…”

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How much better are InGaN/GaN nanodisks than quantum wells—Oscillator strength enhancement and changes in optical properties

Zhang

Lee

Teng

et al. 2014

Applied Physics Letters

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We show over 100-fold enhancement of the exciton oscillator strength as the diameter of an InGaN nanodisk in a GaN nanopillar is reduced from a few micrometers to less than 40 nm, corresponding to the quantum dot limit. The enhancement results from significant strain relaxation in nanodisks less than 100 nm in diameter. Meanwhile, the radiative decay rate is only improved by 10 folds due to strong reduction of the local density of photon states in small nanodisks. Further increase in the radiative decay rate can be achieved by engineering the local density of photon states, such as adding a dielectric coating.InGaN/GaN quantum wells (QWs), with a bandgap tunable over the full visible spectral range, play a vital role in high efficiency visible light emitting diodes (LEDs) and laser diodes 1 . InGaN/GaN quantum dots (QDs) also hold the promise as high temperature quantum photonic devices 2,3 . Unfortunately, a large, strain-induced electric field in III-N heterostructures often severely suppresses the oscillator strength of the exciton and, hence, the radiative decay rate and the internal quantum efficiency (IQE). Since strain is relaxed near free surfaces, nanodisks (NDs) in nanowires, which has a large surfaceto-volume ratio, have been widely considered as a promising solution for improving the IQE of InGaN/GaN photonic devices [4][5][6][7][8][9][10][11] . The accompanying improvement in the radiative decay rate is also important for realizing ultrafast singlephoton sources using InGaN/GaN QDs 3,12 .Despite the observation of enhancements in photoluminescence (PL) intensity and decay rate in InGaN/GaN NDs 4,10,13 , the size-dependent behavior of IQE η int and radiative decay rate γ r , mostly affected by the emitter's oscillator strength f os , remains unclear. Experimental studies using top-down nanopillars reported up to ten-fold enhancement in emission intensity only in nanopillars larger than 100 nm in diameter 10 . However, theoretical studies predicted that strain relaxation is most significant only in the region < 20 nm from the sidewall, suggesting significant improvement of IQE could be possible in small disks ∼ 40 nm in size 9 . Furthermore, no comparisons so far have taken into account the influence of external optical efficiencies on the measured PL intensity, such as input laser absorption efficiency η abs , local density of photon states (LDPS) ρ 14,15 and emission collection efficiency η col 16 , which hinders the extraction of η int , γ r as well as f os .In this work, we systematically compare the PL properties of NDs with diameters ranging from 15 nm to 2 µm. We first present two NDs at the two ends of the diameter range, highlighting their fundamentally different spectral responses to the excitation-induced carrier-screening of piezoelectric fields. We then examine how PL energy, decay time and intensity changes continuously with ND diameter reduction, from which we extract the enhancement of f os , γ r , and η int through careful analysis of various external optical efficiencies.The sample w...

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Luminescence properties of isolated InGaN/GaN quantum dots

Cited by 24 publications

References 12 publications

Surface enhanced luminescence and Raman scattering from ferroelectrically defined Ag nanopatterned arrays

Surface enhanced luminescence and Raman scattering from ferroelectrically defined Ag nanopatterned arrays

Plasmon enhanced fluorescence studies from aligned gold nanorod arrays modified with SiO2 spacer layers

How much better are InGaN/GaN nanodisks than quantum wells—Oscillator strength enhancement and changes in optical properties

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