SITE MULTIPLICITY OF RARE EARTH IONS IN III-NITRIDES

ABSTRACTThis presentation reviews recent lattice location studies of rare earth (RE) ions in GaN by electron emission channelling (EC) and X-ray absorption fine structure (XAFS) techniques. These studies agree that RE ions at low concentrations (whether they are incorporated during growth or introduced later by ion implantation) predominantly occupy Ga substitutional sites, as expected from considerations of charge equivalence. We combine this result with some examples of the well-documented richness of optical spectra of GaN:RE3+ to suggest that the luminescence of these materials may be ascribed to a family of rather similar sites, all of which feature the REGa defect.

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Local Structure of Rare-earth Ions in Alkali Silicate Glasses Studied by Extended X-Ray Absorption Fine Structure

Japanese Journal of Applied Physics ◽

10.7567/jjaps.38s1.168 ◽

1999 ◽

Vol 38 (S1) ◽

pp. 168 ◽

Cited By ~ 4

Author(s):

Hirotaka Yamaguchi ◽

Hiromichi Takebe

Keyword(s):

Fine Structure ◽

Rare Earth ◽

Local Structure ◽

Rare Earth Ions ◽

Silicate Glasses ◽

X Ray ◽

Absorption Fine ◽

Alkali Silicate ◽

X Ray Absorption

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Local Static Distortion of Rare Earth Ions in ROs4Sb12 (R = La, Ce, Pr, Nd, Sm) by Extended X-ray Absorption Fine Structure

Journal of the Physical Society of Japan ◽

10.1143/jpsj.77.063601 ◽

2008 ◽

Vol 77 (6) ◽

pp. 063601 ◽

Cited By ~ 10

Author(s):

Kiyofumi Nitta ◽

Yusuke Omori ◽

Daisuke Kikuchi ◽

Takafumi Miyanaga ◽

Katsuhiko Takegahara ◽

...

Keyword(s):

Fine Structure ◽

Rare Earth ◽

Rare Earth Ions ◽

X Ray ◽

Absorption Fine ◽

Static Distortion ◽

X Ray Absorption

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An extended x-ray absorption fine structure study of rare-earth phosphate glasses near the metaphosphate composition

Journal of Materials Research ◽

10.1557/jmr.1999.0637 ◽

1999 ◽

Vol 14 (12) ◽

pp. 4706-4714 ◽

Cited By ~ 38

Author(s):

R. Anderson ◽

T. Brennan ◽

J. M. Cole ◽

G. Mountjoy ◽

D. M. Pickup ◽

...

Keyword(s):

Fine Structure ◽

Rare Earth ◽

Variable Temperature ◽

Structure Study ◽

Phosphate Glasses ◽

Rare Earth Ions ◽

Glassy Matrix ◽

X Ray ◽

Absorption Fine ◽

X Ray Absorption

A variable-temperature (79, 145, and 293 K) extended x-ray absorption fine structure study, using rare-earth LIII absorption edges, is reported for phosphate glasses doped with rare-earth elements (R, where R = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, and Er) with compositions close to metaphosphate, R(PO3)3. The results yield nearest-neighbor R–O distances that demonstrate the lanthanide contraction in a glassy matrix and an R–O coordination intermediate between 6 and 7 for rare-earth ions with smaller atomic number (Z) and 6 for rare-earth ions with largerZ. Thermal parameters show no significant changes in R–O distances or coordination numbers between 293 and 79 K. There is evidence of an R–P correlation between 3.3 and 3.6 Å and the beginning of a second R–O correlation at approximately 4 Å. No R–R correlations up to a distance of approximately 4 Å were observed.

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Determination of the relative concentrations of rare earth ions by x-ray absorption spectroscopy: Application to terbium mixed oxides

Journal of Physics and Chemistry of Solids ◽

10.1016/0022-3697(86)90033-8 ◽

1986 ◽

Vol 47 (4) ◽

pp. 413-416 ◽

Cited By ~ 11

Author(s):

G. van der Laan ◽

J.C. fuggle ◽

M.P. van Dijk ◽

A.J. Burggraaf ◽

J.-M. Esteva ◽

...

Keyword(s):

Rare Earth ◽

Absorption Spectroscopy ◽

Mixed Oxides ◽

Rare Earth Ions ◽

X Ray ◽

X Ray Absorption

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Extended X-ray Absorption Fine Structure Studies of GaN Epilayers Doped in situ with Er and Eu During Molecular Beam Epitaxy

MRS Proceedings ◽

10.1557/proc-798-y5.10 ◽

2003 ◽

Vol 798 ◽

Cited By ~ 3

Author(s):

V. Katchkanov ◽

J. F. W. Mosselmans ◽

S. Dalmasso ◽

K. P. O'Donnell ◽

R. W. Martin ◽

...

Keyword(s):

Fine Structure ◽

Rare Earth ◽

Molecular Beam Epitaxy ◽

Local Structure ◽

Molecular Beam ◽

X Ray ◽

Absorption Fine ◽

X Ray Absorption ◽

The Eu

ABSTRACTThe local structure around Er and Eu atoms introduced into GaN epilayers was studied by means of Extended X-ray Absorption Fine Structure above the appropriate rare-earth X-ray absorption edge. The samples were doped in situ during growth by Molecular Beam Epitaxy. The formation of ErN clusters was found in samples with high average Er concentrations of 32±6% and 12.4±0.8%, estimated by Wavelength Dispersive X-ray analysis. When the average Er concentration is decreased to 6.0±0.2%, 1.6±0.2% and 0.17±0.02%, Er is found in localised clusters of ErGaN phase with high local Er content. Similar behaviour is observed for Eu-doped samples. For an average Eu concentration of 30.5±0.5% clusters of pure EuN occur. Decreasing the Eu concentration to 10.4±0.5% leads to EuGaN clusters with high local Eu content. However, for a sample with an Eu concentration of 14.2±0.5% clustering of Eu was not observed.

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Fluorescence Extended X-Ray Absorption Fine Structure Study on Local Structures of Rare-Earth-Doped InGaGdN

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1133.429 ◽

2016 ◽

Vol 1133 ◽

pp. 429-433

Author(s):

Siti Nooraya Mohd Tawil ◽

Shuichi Emura ◽

Daivasigamani Krishnamurthy ◽

Hajime Asahi

Keyword(s):

Fine Structure ◽

Rare Earth ◽

Nearest Neighbor ◽

Structure Study ◽

Edge Structure ◽

X Ray ◽

Local Structures ◽

Absorption Fine ◽

X Ray Absorption

Local structures around gadolinium atoms in rare-earth (RE)-doped InGaGdN thin films were studied by means of fluorescence extended X-ray absorption fine structure (EXAFS) measured at the Gd LIII-edges. The samples were doped with Gd in-situ during growth by plasma-assisted molecular beam epitaxy (PAMBE). Gd LIII-edge EXAFS signal from the GaGdN, GdN and Gd foil were also measured as reference. The X-ray absorption near edge structure (XANES) spectra around Gd LIII absorption edge of InGaGdN samples observed at room temperature indicated the enhancement of intensities with the increase of Gd composition. Further EXAFS analysis inferred that the Gd atoms in InGaN were surrounded by similar atomic shells as in the case of GaGdN with the evidence indicating majority of Gd atoms substituted into Ga sites of InGaGdN. A slight elongation of bond length for the 2nd nearest-neighbor (Gd–Ga) of sample with higher Gd concentration was also observed.

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