scholarly journals Synthesis and Characterization of Doped and Undoped ZnO Nanostructures

2006 ◽  
Vol 12 (4) ◽  
pp. 327-330 ◽  
Author(s):  
Katie E. McBean ◽  
Matthew R. Phillips ◽  
Ewa M. Goldys
Keyword(s):  
Rare Earth ◽  
Earth Metal ◽  
Rare Earth Ions ◽  
Near Band Edge ◽  
Band Edge Emission ◽  
Ethanolic Solution ◽  
Edge Emission ◽  
Rare Earth Doped ◽  
The Rare Earth

Zinc oxide (ZnO) nanoparticles have been produced using precipitation methods from ethanolic solution. Rare-earth metal doping was performed, and the effect of lithium codoping on the luminescence properties of the rare-earth doped products was assessed. The resulting particles were characterized using cathodoluminescence and scanning electron microscopy. It was found that lithium significantly enhanced the cathodoluminescence signal from the rare-earth ions, which has been attributed to the increased integration of the rare-earth ions into the ZnO structure. The nanophase ZnO products were also annealed in argon, hydrogen, and oxygen, with hydrogen being the most successful for removing the broad defect emission present in as-grown samples and enhancing the ZnO near band edge emission.

Synthesis and characterization of the novel rare earth orthophosphates Y0.5Er0.5PO4 and Y0.5Yb0.5PO4

2016 ◽  
Vol 71 (1) ◽  
pp. 65-70 ◽  
Author(s):  
Daniel Schildhammer ◽  
Lucas L. Petschnig ◽  
Gerda Fuhrmann ◽  
Gunter Heymann ◽  
Martina Tribus ◽  
...  
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Structural Parameters ◽  
Earth Metal ◽  
Rare Earth Ions ◽  
The Novel ◽  
X Ray Diffraction ◽  
The Individual ◽  
New Compounds ◽  
The Rare Earth

AbstractThe new mixed rare earth (RE) orthophosphates Y0.5Er0.5PO4 and Y0.5Yb0.5PO4 were synthesized by a classical solid state reaction in an electrical furnace at 1200 °C. As starting materials, the corresponding rare earth oxides and diammonium hydrogen phosphate were used. The powder diffraction analyses revealed that the new compounds Y0.5Er0.5PO4 and Y0.5Yb0.5PO4 crystallize in a zircon-type structure being isostructural with the rare earth orthophosphate YPO4. Y0.5Er0.5PO4 and Y0.5Yb0.5PO4 crystallize in the tetragonal space group I41/amd (no. 141) with four formula units in the unit cell. The structural parameters based on Rietveld refinements are a = 687.27(2), c = 601.50(2) pm, V = 0.28412(1) nm3, Rp= 0.0143, and Rwp = 0.0186 (all data) for Y0.5Er0.5PO4 and a = 684.61(2), c = 599.31(2) pm, V = 0.28089(2) nm3, Rp = 0.0242, and Rwp = 0.0313 (all data) for Y0.5Yb0.5PO4. Furthermore, the structure of Y0.5Er0.5PO4 was refined from single-crystal X-ray diffraction data: a = 687.78(5), c = 601.85(4) pm, V = 0.28470(5) nm3, R1= 0.0165, and wR2 = 0.0385 (all data). In both compounds, the rare earth metal ions are eightfold coordinated by oxygen atoms, forming two unique interlocking tetrahedra with two individual RE–O distances. The tetrahedral phosphate groups [PO4]3– are slightly distorted in both compounds. The individual rare earth ions share a common position (Wyckoff site 4a). The presence of two rare earth ions in the structures of the new orthophosphates Y0.5Er0.5PO4 and Y0.5Yb0.5PO4 was additionally confirmed by single-crystal EDX spectroscopy revealing a ratio of 1:1.

scholarly journals RE-Based Inorganic-Crystal Nanofibers Produced by Electrospinning for Photonic Applications

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2679
Author(s):  
Alessandra Toncelli
Keyword(s):  
Rare Earth ◽  
Near Infrared ◽  
High Surface ◽  
High Surface Area ◽  
Volume Ratio ◽  
Rare Earth Ions ◽  
Polymer Materials ◽  
Electrospinning Technique ◽  
Rare Earth Doped

Electrospinning is an effective and inexpensive technique to grow polymer materials in nanofiber shape with exceptionally high surface-area-to-volume ratio. Although it has been known for about a century, it has gained much interest in the new millennium thanks to its low cost and versatility, which has permitted to obtain a large variety of multifunctional compositions with a rich collection of new possible applications. Rare-earth doped materials possess many remarkable features that have been exploited, for example, for diode pumped bulk solid-state lasers in the visible and near infrared regions, or for biomedical applications when grown in nanometric form. In the last few decades, electrospinning preparation of rare-earth-doped crystal nanofibers has been developed and many different materials have been successfully grown. Crystal host, crystal quality and nanosized shape can deeply influence the optical properties of embedded rare earth ions; therefore, a large number of papers has recently been devoted to the growth and characterization of rare earth doped nanofibers with the electrospinning technique and an up-to-date review of this rapidly developing topic is missing; This review paper is devoted to the presentation of the main results obtained in this field up to now with particular insight into the optical characterization of the various materials grown with this technique.

Er3+-Doped Silicon Prepared by Laser Doping

1993 ◽  
Vol 301 ◽  
Author(s):  
T. Asatsuma ◽  
P. Dodd ◽  
J. F. Donegan ◽  
J. G. Lunney ◽  
J. Hegarty
Keyword(s):  
Rare Earth ◽  
Pulsed Laser ◽  
Earth Metal ◽  
Optically Active ◽  
Rare Earth Ions ◽  
Molten Layer ◽  
Laser Doping ◽  
Doped Silicon ◽  
Preliminary Study ◽  
The Rare Earth

ABSTRACTWe have carried out an investigation of the laser doping of Si with rare-earth ions. In this technique a silicon surface coated with a thin layer of the rare-earth metal is melted with a pulsed laser, the dopant is mixed in the molten layer, and incorporated in the crystal during regrowth. Er was chosen for the main part of our work as it is the best characterized of the rare-earth ions in Si. Luminescence is observed around 1.54µm and is assigned to optical transitions on Er3+ ions. This preliminary study shows that this new technique is viable for the production of optically active Er3+ in Si.

Analysis of thermal glow curves in rare-earth-doped CaF2 crystals

1969 ◽  
Vol 47 (15) ◽  
pp. 1637-1638 ◽  
Author(s):  
M. Schlesinger ◽  
A. Krishna Menon
Keyword(s):  
Rare Earth ◽  
Thermal Activation ◽  
Activation Energies ◽  
Rare Earth Ions ◽  
Hole Trapping ◽  
Order Of Kinetics ◽  
Close Proximity ◽  
Rare Earth Doped ◽  
Trapping Sites ◽  
The Rare Earth

The main parameters, that is, thermal activation energies, frequency factors, and order of kinetics, are calculated for some glow peaks in rare-earth-doped CaF2. From the results, it is inferred that the hole trapping sites are in close proximity to the rare-earth ions.

Rare-Earth Doped Silicon-Rich Silica: Evidence for Energy Transfer between Silicon Microclusters and Rare-Earth Ions

1994 ◽  
Vol 358 ◽  
Author(s):  
A.J. Kenyon ◽  
P.F. Trwoga ◽  
M. Federighi ◽  
C.W. Pitt
Keyword(s):  
Rare Earth ◽  
Visible Region ◽  
Rare Earth Ions ◽  
Excitation Wavelength ◽  
Rare Earth Ion ◽  
Absorption Bands ◽  
Strong Luminescence ◽  
Doped Silicon ◽  
Rare Earth Doped ◽  
The Rare Earth

ABSTRACTWe report the fabrication of rare-earth doped silicon-rich silica thin films by PECVD. The films exhibit absorption edges in the visible region of the optical spectrum consistent with the presence of silicon microclusters. Weak visible photoluminescence due to silicon microclusters is observed. In addition, strong luminescence from the rare-earth ion is obtained even when excited away from characteristic absorption bands; indeed, the luminescence intensity is largely independent of excitation wavelength below 514 nm. We ascribe this to excitation of silicon microclusters followed by an efficient transfer of energy to the rare-earth ions.The very broad absorption of this material opens up the possibility for flashlamp-pumped optoelectronic devices. In addition, we report the fabrication of silicon-rich silica films by PECVD. We show that the optical properties of these films are consistent with the presence of silicon microclusters and show absorption spectra similar to those of the rare-earth doped silicon-rich silica samples. This supports the hypothesis that the principal absorbing species in the rare-earth doped films is microclustered silicon

scholarly journals Growth, Doping and Characterization of AlxGa1−xN Thin Film Alloys on 6H-SiC(0001) Substrates

1996 ◽  
Vol 1 ◽  
Author(s):  
M. D. Bremser ◽  
W. G. Perry ◽  
T. Zheleva ◽  
N. V. Edwards ◽  
O. H. Nam ◽  
...  
Keyword(s):  
Near Band Edge ◽  
Band Edge Emission ◽  
Initial Growth ◽  
Silicon Doping ◽  
Edge Emission ◽  
Cross Sectional ◽  
Aln Buffer ◽  
Buffer Structure ◽  
Coherent Interfaces

Thin films of AlxGa1−xN (0.05 ≤ x ≤ 0.96) having smooth surfaces were deposited directly on both vicinal and on-axis 6H-SiC(0001) substrates. Cross-sectional TEM of Al0.13Ga0.87N revealed stacking faults near the SiC/Nitride alloy interface and numerous threading dislocations. EDX, AES and RBS were used to determine the compositions, which were paired with their respective CL near band-edge emission energies. A negative bowing parameter was determined. The CL emission energies were similar to the bandgap energies obtained by SE. FE-AES of the initial growth of Al0.2Ga0.8N revealed an aluminum rich layer near the interface. N-type (silicon) doping was achieved for AlxGa1−xN for 0.12 ≤ x ≤ 0.42. Al0.2Ga0.8N/GaN superlattices were fabricated with coherent interfaces. Additionally, HEMT structures using an AlN/GaN/AlN buffer structure were fabricated.

scholarly journals High-pressure synthesis of REB5O8(OH)2 (RE = Ho, Er, Tm)

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Michael Zoller ◽  
Hubert Huppertz
Keyword(s):  
High Pressure ◽  
Rare Earth ◽  
Ir Spectroscopy ◽  
Earth Metal ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure Solution ◽  
Pressure Synthesis ◽  
The Rare Earth

AbstractThe rare earth oxoborates REB5O8(OH)2 (RE = Ho, Er, Tm) were synthesized in a Walker-type multianvil apparatus at a pressure of 2.5 GPa and a temperature of 673 K. Single-crystal X-ray diffraction data provided the basis for the structure solution and refinement. The compounds crystallize in the monoclinic space group C2 (no. 5) and are composed of a layer-like structure containing dreier and sechser rings of corner sharing [BO4]5− tetrahedra. The rare earth metal cations are coordinated between two adjacent sechser rings. Further characterization was performed utilizing IR spectroscopy.

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