Role of Si in the Luminescence of AlN:Eu,Si Phosphors

Dierre, Benjamin; Yuan, Xinjian; Inoue, Kazuo; Hirosaki, Naoto; Xie, Rong‐Jun; Sekiguchi, Takashi

doi:10.1111/j.1551-2916.2009.03048.x

Cited by 40 publications

(55 citation statements)

References 13 publications

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“…The studied samples were rare-earth doped oxynitride phosphors (Ca and Yb codoped α-SiAlON and Eu-doped AlN) synthesized by gas-pressure sintering [9][10][11][12][13][14] [17,18], nanoparticles (vapor method) [19], nanoflowers (hydrothermal method) [20], tetrapods composed of nanorods (catalyst-free vapor-solid growth) [21], polycrystals [22] and single crystals (hydrothermal synthesis) [23].…”

Section: Samplesmentioning

confidence: 99%

“…As for the variation of concentration/composition, the combination of CL with TEM, EDS or Auger spectroscopy can result in a better understanding of the origin of the luminescence [48,49]. Here, we illustrate this aspect by the analysis of europium doping of AlN using the combination of CL and EDS [14]. Figure 8 shows the normalized CL spectra of undoped AlN and AlN:Eu (AlN doped with 0.2% Eu).…”

Section: Comparison With Other E-beam Techniquesmentioning

confidence: 99%

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Low-energy cathodoluminescence microscopy for the characterization of nanostructures

Dierre

Yuan

Sekiguchi

2010

Science and Technology of Advanced Materials

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Spatially and spectrally resolved low-energy cathodoluminescence (CL) microscopy was applied to the characterization of nanostructures. CL has the advantage of revealing not only the presence of luminescence centers but also their spatial distribution. The use of electrons as an excitation source allows a direct comparison with other electron-beam techniques. Thus, CL is a powerful method to correlate luminescence with the sample structure and to clarify the origin of the luminescence. However, caution is needed in the quantitative analysis of CL measurements. In this review, the advantages of cathodoluminescence for qualitative analysis and disadvantages for quantitative analysis are presented on the example of nanostructures.

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Section: Samplesmentioning

confidence: 99%

Section: Comparison With Other E-beam Techniquesmentioning

confidence: 99%

Low-energy cathodoluminescence microscopy for the characterization of nanostructures

Dierre

Yuan

Sekiguchi

2010

Science and Technology of Advanced Materials

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“…Thus, the structural, chemical or electrical properties can also be obtained. The combination of these techniques with CL results in a better understanding of the origin of the localized structures of Sialon phosphors [14][15][16][17][18][19][20] . CL investigations can be performed by means of different types of electron-beam sources 13 .…”

Section: +mentioning

confidence: 99%

“…NOTE: Keep the same conditions for the duration of the sintering. Heating temperature and duration are different depending on the materials [14][15][16][17][18][19][20] . 4.…”

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confidence: 99%

Low-energy Cathodoluminescence for (Oxy)Nitride Phosphors

Cho

Dierre

Sekiguchi

et al. 2016

JoVE

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Nitride and oxynitride (Sialon) phosphors are good candidates for the ultraviolet and visible emission applications. High performance, good stability and flexibility of their emission properties can be achieved by controlling their composition and dopants. However, a lot of work is still required to improve their properties and to reduce the production cost. A possible approach is to correlate the luminescence properties of the Sialon particles with their local structural and chemical environment in order to optimize their growth parameters and find novel phosphors. For such a purpose, the low-voltage cathodoluminescence (CL) microscopy is a powerful technique. The use of electron as an excitation source allows detecting most of the luminescence centers, revealing their luminescence distribution spatially and in depth, directly comparing CL results with the other electron-based techniques, and investigating the stability of their luminescence properties under stress. Such advantages for phosphors characterization will be highlighted through examples of investigation on several Sialon phosphors by low-energy CL.

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“…17 The correlation of the local compositional and luminescent properties has the potential to lead to a more profound understanding of the behavior of a phosphor and luminescence mechanisms in general. This technique has been successfully applied to study local compositional differences, [17][18][19][20] dopant clustering, 21 impurity phases 22,23 and particle size inhomogeneity 21,24,25 in phosphors. Single particle studies thus increase our knowledge on phosphor properties and often lead to the discovery of interesting novel phenomena.…”

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confidence: 99%

Microscopic Study of Dopant Distribution in Europium Doped SrGa₂S₄: Impact on Thermal Quenching and Phosphor Performance

Martin¹,

Poelman²,

Smet³

et al. 2017

ECS J. Solid State Sci. Technol.

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White light emitting diodes start to dominate lighting and display applications. However, the properties of the phosphors used in these devices strongly depend on synthesis conditions. A better understanding of how performance-determining mechanisms such as thermal quenching are influenced by synthesis conditions and sample composition is necessary to achieve the required standards in a goal-oriented strategy. In this paper, a microscopic thermal quenching study on green-emitting SrGa 2 S 4 :Eu 2+ phosphors by means of cathodoluminescence spectroscopy and energy dispersive X-ray analysis in a scanning electron microscope is used to extend our knowledge beyond averaged information obtained on bulk material. Elemental and cathodoluminescence mapping at different temperatures made it possible to determine thermal quenching profiles for sub-micrometer sized areas. These revealed a broad range of local quenching temperatures for samples with ill-distributed dopant ions. For the associated activation energy an upper limit of 0.61 eV was identified, corresponding to the intrinsic thermal quenching of isolated europium ions. Furthermore, the results confirm a previously suggested thermal quenching model which involves the presence of both isolated and clustered dopant ions. Inorganic luminescent materials or phosphors are currently applied on a large scale in various novel technologies. Most notably, white light-emitting diodes (LEDs), which are applied in lighting and display technologies, rely on high-performance phosphors. [1][2][3] Here, the emission of a blue light source, based on a Ga 1-x In x N LED chip is partly absorbed by the phosphor blend that is applied on top of this chip or in a remote fashion. [4][5][6] The phosphor re-emits the absorbed energy as green, yellow and red light, which is mixed with the remaining blue LED emission as to get an overall white emission. This requires subtle fine-tuning, both in terms of material composition, 7,8 as well as device manufacturing 5,9 to achieve white LED devices with the desired properties.From the materials point of view, phosphor properties are highly dependent on synthesis conditions, often in an unpredictable and hardto-control way. This can be attributed to an incomplete understanding of the underlying physical mechanisms for various macroscopic properties. 10 As an example, thermal quenching (TQ), i.e. the decreased internal quantum efficiency of luminescent materials at elevated temperatures, has been attributed to various causes, either intrinsic to the luminescent center itself or due to external influences such as the presence of defects or the local clustering of luminescent ions. 10,11 The undetermined nature of TQ makes it difficult to engineer synthesis routines to yield phosphors with a minimized TQ and an optimized performance.Phosphors are generally studied at the macroscopic level, i.e measurements are typically performed on milligram quantities, a scale which is of relevance for applications. Nonetheless, if materials are inhomogeneous in terms...

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Role of Si in the Luminescence of AlN:Eu,Si Phosphors

Cited by 40 publications

References 13 publications

Low-energy cathodoluminescence microscopy for the characterization of nanostructures

Low-energy cathodoluminescence microscopy for the characterization of nanostructures

Low-energy Cathodoluminescence for (Oxy)Nitride Phosphors

Microscopic Study of Dopant Distribution in Europium Doped SrGa₂S₄: Impact on Thermal Quenching and Phosphor Performance

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Role of Si in the Luminescence of AlN:Eu,Si Phosphors

Cited by 40 publications

References 13 publications

Low-energy cathodoluminescence microscopy for the characterization of nanostructures

Low-energy cathodoluminescence microscopy for the characterization of nanostructures

Low-energy Cathodoluminescence for (Oxy)Nitride Phosphors

Microscopic Study of Dopant Distribution in Europium Doped SrGa2S4: Impact on Thermal Quenching and Phosphor Performance

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Product

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Microscopic Study of Dopant Distribution in Europium Doped SrGa₂S₄: Impact on Thermal Quenching and Phosphor Performance