Commissioning of the Spherical Grating Monochromator Soft X-ray Spectroscopy Beamline at the Canadian Light Source

Regier, Tom; Paulsen, Jane S.; Wright, G.M.; Coulthard, I.; Tan, K. H.; Sham, T. K.; Blyth, R. I. R.

doi:10.1063/1.2436101

Cited by 74 publications

(65 citation statements)

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“…Measurements were carried out under a high vacuum of 10 −7 Torr or better. Absorption measurements at the nitrogen K-edge were made at the Spherical Grating Monochromator (SGM) beamline at the Canadian light source, [ 33,34 ] with a monochromator resolving power ( E /Δ E ) of about 2000. These spectra were collected as the partial fl uorescence yield (PFY).…”

Section: Methodsmentioning

confidence: 99%

Electronic Structure, Bandgap, and Thermal Quenching of Sr[Mg₃SiN₄]:Eu²⁺ in Comparison to Sr[LiAl₃N₄]:Eu²⁺

Tolhurst

Schmiechen

Pust

et al. 2015

Advanced Optical Materials

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from a lack of emissions in the red-spectral region. Other designs are therefore preferable for high-quality illumination. [ 3 ] If pc-LEDs are to be used in general lighting they must be effi cient, have high color rendering and temperature-stable emission spectra. Two promising designs meeting these requirements are UV and blue LED chips, using three and two phosphors, respectively. Even these designs have encountered challenges, such as the ineffi ciency of the available red phosphors. [ 2 ] The discovery of new, effi cient red phosphors is therefore of the utmost importance. With constantly improving effi ciency and color rendition, along with dropping production costs, pc-LEDs can be expected to replace traditional lighting methods in the near future. [ 4 ] Rare earth (RE)-doped nitride phosphors based on condensed tetrahedral networks, with their tendency to exhibit highly effi cient and stable emissions, are promising candidates for the next generation of phosphors for pc-LEDs. [ 3,4 ] However, not all nitride matrices are equal. The polarizability of the ligands, covalency, and crystal fi eld splitting (CFS) experienced by the RE dopants are all key parameters. [ 4 ] Recently, the promising, red phosphors Sr[Mg 3 SiN 4 ]:Eu 2+ (SMS) and Sr[LiAl 3 N 4 ]:Eu 2+ (SLA) have been reported. [ 5,6 ] These highly condensed nitrides show narrow-band emissions in the red-spectral region. SMS shows λ em = 615 nm with an FWHM of 43 nm, while SLA shows λ em = 650 nm with an FWHM of 50 nm. Narrow emissions in this region are of interest because they are more likely to fall within the sensitivity range of the human eye. Emissions outside of this range, which often occur with a large FWHM in the red-spectral region, lead to wasted energy input and additional heating in the device. This work will focus on characterizing the electronic structure of SMS, which exhibits the narrowest emissions to date for a red-emitting, Eu 2+ -doped phosphor. [ 5 ] A combination of X-ray spectroscopy and density functional theory (DFT) calculations is used in this characterization. The thermal quenching data for the visible, Eu 2+ 5d→4f emissions of SMS and SLA are also modeled and compared. Where SMS shows poor emission stability with increases in temperature, SLA shows exceptional stability. However, SMS emits at a shorter wavelength, which may be more useful for certain applications. Between these phosphors many ideal characteristics for use in pc-LEDs are present. Their comparison (SLA), which shows different, yet exceptional emission characteristics in the red-spectral region. It is found that SMS has an indirect band gap of 3.28 ± 0.20 eV, strong uniformity in the density of states of its nonequivalent nitrogen sites, and an estimated energetic separation between the lowest Eu 2+ 5d state and the conduction band of ≈0.13 eV. The Eu 2+ 5d-conduction band separation in SLA is found to be ≈0.28 eV, which points to why the visible emissions of SLA, and not SMS, show outstanding thermal stability. A bonding scheme explaining the band gap di...

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Section: Methodsmentioning

confidence: 99%

Electronic Structure, Bandgap, and Thermal Quenching of Sr[Mg₃SiN₄]:Eu²⁺ in Comparison to Sr[LiAl₃N₄]:Eu²⁺

Tolhurst

Schmiechen

Pust

et al. 2015

Advanced Optical Materials

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“…Al K-edge, Al L 2,3 -edge, and Si L 2,3 -edge XANES measurements where conducted at the Canadian Light Source (Saskatoon, Canada) using the high resolution spherical grating monochromator beamline (SGM; Regier et al, 2007) and the variable line spacing plane grating monochromator beamline (VLS-PGM; Hu et al, 2007). Si K-edge spectra were collected on the DCM beamline over the region of 1825-1890 eV using step intervals of 0.5 eV (1825-1840 eV) and 0.25 eV (1840-1890 eV) with a 1 s dwell time.…”

Section: Xanes Analysesmentioning

confidence: 99%

Investigation of acidic dissolution of mixed clays between pH 1.0 and −3.0 using Si and Al X-ray absorption near edge structure

Shaw

Peak

Hendry

2009

Geochimica et Cosmochimica Acta

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“…Aluminum K-edge X-ray absorption near edge spectroscopy (XANES) was performed on unwashed solid samples at the spherical grating monochromator (SGM) beamline (Regier et al, 2007) at the Canadian Light Source synchrotron (Saskatoon, Canada). Aluminum reference compounds were either synthesized or commercially produced.…”

Section: Sample Analysismentioning

confidence: 99%

Precipitation of aluminum and magnesium secondary minerals from uranium mill raffinate (pH 1.0–10.5) and their controls on aqueous contaminants

Robertson

Hendry

Essilfie-Dughan

et al. 2016

Applied Geochemistry

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Commissioning of the Spherical Grating Monochromator Soft X-ray Spectroscopy Beamline at the Canadian Light Source

Cited by 74 publications

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Electronic Structure, Bandgap, and Thermal Quenching of Sr[Mg₃SiN₄]:Eu²⁺ in Comparison to Sr[LiAl₃N₄]:Eu²⁺

Electronic Structure, Bandgap, and Thermal Quenching of Sr[Mg₃SiN₄]:Eu²⁺ in Comparison to Sr[LiAl₃N₄]:Eu²⁺

Investigation of acidic dissolution of mixed clays between pH 1.0 and −3.0 using Si and Al X-ray absorption near edge structure

Precipitation of aluminum and magnesium secondary minerals from uranium mill raffinate (pH 1.0–10.5) and their controls on aqueous contaminants

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Commissioning of the Spherical Grating Monochromator Soft X-ray Spectroscopy Beamline at the Canadian Light Source

Cited by 74 publications

References 0 publications

Electronic Structure, Bandgap, and Thermal Quenching of Sr[Mg3SiN4]:Eu2+ in Comparison to Sr[LiAl3N4]:Eu2+

Electronic Structure, Bandgap, and Thermal Quenching of Sr[Mg3SiN4]:Eu2+ in Comparison to Sr[LiAl3N4]:Eu2+

Investigation of acidic dissolution of mixed clays between pH 1.0 and −3.0 using Si and Al X-ray absorption near edge structure

Precipitation of aluminum and magnesium secondary minerals from uranium mill raffinate (pH 1.0–10.5) and their controls on aqueous contaminants

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Product

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Electronic Structure, Bandgap, and Thermal Quenching of Sr[Mg₃SiN₄]:Eu²⁺ in Comparison to Sr[LiAl₃N₄]:Eu²⁺

Electronic Structure, Bandgap, and Thermal Quenching of Sr[Mg₃SiN₄]:Eu²⁺ in Comparison to Sr[LiAl₃N₄]:Eu²⁺