scholarly journals Engineering defect clusters in distorted NaMgF3 perovskite and their important roles in tuning the emission characteristics of Eu3+ dopant ion

RSC Advances ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 5815-5831
Author(s):  
Sumanta Mukherjee ◽  
Nimai Pathak ◽  
Debarati Das ◽  
Dhanadeep Dutta
Keyword(s):  
Emission Spectrum ◽  
Emission Characteristics ◽  
Defect Engineering ◽  
Defect Clusters ◽  
Photoluminescence Decay ◽  
Decay Profile ◽  
The Eu

Defect engineering in distorted NaMgF3 can be achieved by doping different amounts of dopant (Eu3+) and co-dopant (Li+) ions, which has a significant impact on the emission spectrum and photoluminescence decay profile of the Eu3+ ion.

scholarly journals Hysteretic Photochromic Switching (HPS) in Doubly Doped GaN(Mg):Eu—A Summary of Recent Results

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1800 ◽  
Author(s):  
Paul Edwards ◽  
Kevin O’Donnell ◽  
Akhilesh Singh ◽  
Douglas Cameron ◽  
Katharina Lorenz ◽  
...  
Keyword(s):  
Rare Earth ◽  
Quantum Information ◽  
Emission Spectrum ◽  
Recent Work ◽  
Photoluminescence Spectrum ◽  
Rare Earth Ion ◽  
Light Emitting ◽  
P Type ◽  
Induced Changes ◽  
The Eu

Europium is the most-studied and least-well-understood rare earth ion (REI) dopant in GaN. While attempting to increase the efficiency of red GaN light-emitting diodes (LEDs) by implanting Eu+ into p-type GaN templates, the Strathclyde University group, in collaboration with IST Lisbon and Unipress Warsaw, discovered hysteretic photochromic switching (HPS) in the photoluminescence spectrum of doubly doped GaN(Mg):Eu. Our recent work, summarised in this contribution, has used time-, temperature- and light-induced changes in the Eu intra-4f shell emission spectrum to deduce the microscopic nature of the Mg-Eu defects that form in this material. As well as shedding light on the Mg acceptor in GaN, we propose a possible role for these emission centres in quantum information and computing.

scholarly journals Hysteretic Photochromic Switching (HPS) in Doubly Doped GaN(Mg):Eu—A Summary of Recent Results

2018 ◽  
Author(s):  
Paul R. Edwards ◽  
Kevin P. O'Donnell ◽  
Akhilesh K. Singh ◽  
Douglas Cameron ◽  
Katharina Lorenz ◽  
...  
Keyword(s):  
Rare Earth ◽  
Quantum Information ◽  
Emission Spectrum ◽  
Recent Work ◽  
Photoluminescence Spectrum ◽  
Rare Earth Ion ◽  
Light Emitting ◽  
P Type ◽  
Induced Changes ◽  
The Eu

Europium is the most-studied and least-well-understood rare earth ion (REI) dopant in GaN. While attempting to increase the efficiency of red GaN light-emitting diodes (LEDs) by implanting Eu+ into p-type GaN templates, the Strathclyde University group, in collaboration with IST Lisbon and Unipress Warsaw, discovered hysteretic photochromic switching (HPS) in the photoluminescence spectrum of doubly doped GaN(Mg):Eu. Our recent work, summarised in this contribution, has used time-, temperature- and light-induced changes in the Eu intra-4f shell emission spectrum to deduce the microscopic nature of the Mg-Eu defects that form in this material. As well as shedding light on the Mg acceptor in GaN, we propose a possible role for these emission centres in quantum information and computing.

Tuning field-emission characteristics of ZnO nanorods through defect engineering via O+ ion irradiation

2020 ◽  
Vol 128 (5) ◽  
pp. 054304
Author(s):  
Avanendra Singh ◽  
Kartik Senapati ◽  
Ranveer Singh ◽  
Parasmani Rajput ◽  
Tapobrata Som ◽  
...  
Keyword(s):  
Field Emission ◽  
Ion Irradiation ◽  
Zno Nanorods ◽  
Emission Characteristics ◽  
Defect Engineering

Evolution of different defect clusters in Eu3+ doped KMgF3 and Eu3+, Li+ co-doped KMgF3 compounds and the immediate impact on the phosphor characteristics

2020 ◽  
Vol 8 (21) ◽  
pp. 7149-7161 ◽  
Author(s):  
Nimai Pathak ◽  
Sumanta Mukherjee ◽  
Debarati Das ◽  
Dhanadeep Dutta ◽  
Smruti Dash ◽  
...  
Keyword(s):  
Local Structure ◽  
Emission Characteristics ◽  
Defect Clusters ◽  
Co Doped

Different type of defect clusters were found to exist in Eu3+:KMgF3 and Li+, Eu3+:KMgF3 compounds, which can change the surrounding local structure of Eu3+ dopant ion. This resulted in different emission characteristics of Eu3+ ions, which can change the phosphor characteristics of the compounds.

Combustion Synthesis and Luminescence Properties of Li2Ca1-x-ySiO4: xEu3+, ySm3+ Phosphors

2015 ◽  
Vol 814 ◽  
pp. 384-388
Author(s):  
Ce Zhao ◽  
Ke Hui Qiu ◽  
Xia He ◽  
Guo Yin Yan ◽  
Si Zhu Chen
Keyword(s):  
Phase Composition ◽  
Emission Spectrum ◽  
Charge Transfer Band ◽  
Combustion Method ◽  
Concentration Quenching ◽  
Excitation Spectra ◽  
Diffraction Peaks ◽  
Co Doped ◽  
Sensitization Effect ◽  
The Eu

A series of red-emitting phosphors, Eu3+-doped and Eu3+ with Sm3+ co-doped Li2CaSiO4, were prepared by the combustion method. The phase composition was investigated by XRD, and photoluminescent properties were characterized by fluorescent spectrophotometer. The results show that the diffraction peaks of samples all match well with that of Li2CaSiO4 [JCPDS NO. 27-0290]. The excitation spectra consists of the broadband and the sharp lines, which are assigned to the charge transfer band (CTB) of Eu3+→O2– and the typical intra-4f transitions of the Eu3+ ions, respectively. The emission spectrum covers the characteristic f-f transitions of Eu3+, namely, 5D0→7F1 (596 nm), 5D0→7F2 (620 nm), 5D0→7F3 (657 nm) and 5D0→7F4 (705 nm). The concentration quenching occurs when Eu3+ mol fraction equals to 9%. When Eu3+and Sm3+ were co-doped, the luminous intensity of the emission spectrum was superior to the Eu3+ mono-doped, which explains the Sm3+ has a sensitization effect for Eu3+.

Models of Thermodynamic Properties of Prominences

1979 ◽  
Vol 44 ◽  
pp. 349-355
Author(s):  
R.W. Milkey
Keyword(s):  
Thermodynamic Properties ◽  
Mass Transport ◽  
Emission Spectrum ◽  
Thermodynamic Parameters ◽  
Working Group ◽  
Physical Processes ◽  
Theoretical Concepts ◽  
Group 3 ◽  
Observational Techniques

The focus of discussion in Working Group 3 was on the Thermodynamic Properties as determined spectroscopically, including the observational techniques and the theoretical modeling of physical processes responsible for the emission spectrum. Recent advances in observational techniques and theoretical concepts make this discussion particularly timely. It is wise to remember that the determination of thermodynamic parameters is not an end in itself and that these are interesting chiefly for what they can tell us about the energetics and mass transport in prominences.

Annealing Of Radiation Damage in Tungsten

1970 ◽  
Vol 28 ◽  
pp. 412-413
Author(s):  
Robert C. Rau ◽  
John Moteff
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Radiation Damage ◽  
Thermal Annealing ◽  
Neutron Fluence ◽  
Dislocation Loops ◽  
Defect Clusters ◽  
Polycrystalline Tungsten ◽  
Transmission Electron ◽  
Radiation Induced

Transmission electron microscopy has been used to study the thermal annealing of radiation induced defect clusters in polycrystalline tungsten. Specimens were taken from cylindrical tensile bars which had been irradiated to a fast (E > 1 MeV) neutron fluence of 4.2 × 1019 n/cm2 at 70°C, annealed for one hour at various temperatures in argon, and tensile tested at 240°C in helium. Foils from both the unstressed button heads and the reduced areas near the fracture were examined.Figure 1 shows typical microstructures in button head foils. In the unannealed condition, Fig. 1(a), a dispersion of fine dot clusters was present. Annealing at 435°C, Fig. 1(b), produced an apparent slight decrease in cluster concentration, but annealing at 740°C, Fig. 1(C), resulted in a noticeable densification of the clusters. Finally, annealing at 900°C and 1040°C, Figs. 1(d) and (e), caused a definite decrease in cluster concentration and led to the formation of resolvable dislocation loops.

Examination of Extra Electron Diffraction Spots Observed in Deuterium-Irradiated Silicon by Using Parallel Electron Beam Illumination

1990 ◽  
Vol 48 (2) ◽  
pp. 490-491
Author(s):  
Ryuichiro Oshima ◽  
Shoichiro Honda ◽  
Tetsuo Tanabe
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Silicon Single Crystal ◽  
Mixed Solution ◽  
Parallel Beam ◽  
Defect Clusters ◽  
Float Zone ◽  
Transmission Electron ◽  
Extra Electron ◽  
Diffraction Patterns

In order to examine the origin of extra diffraction spots and streaks observed in selected area diffraction patterns of deuterium irradiated silicon, systematic diffraction experiments have been carried out by using parallel beam illumination.Disc specimens 3mm in diameter and 0.5mm thick were prepared from a float zone silicon single crystal(B doped, 7kΩm), and were chemically thinned in a mixed solution of nitric acid and hydrogen fluoride to make a small hole at the center for transmission electron microscopy. The pre-thinned samples were irradiated with deuterium ions at temperatures between 300-673K at 20keV to a dose of 1022ions/m2, and induced lattice defects were examined under a JEOL 200CX electron microscope operated at 160kV.No indication of formation of amorphous was obtained in the present experiments. Figure 1 shows an example of defects induced by irradiation at 300K with a dose of 2xl021ions/m2. A large number of defect clusters are seen in the micrograph.

Tem analysis of multiple-energy arsenic implanted and Rta'd silicon

1987 ◽  
Vol 45 ◽  
pp. 246-247
Author(s):  
R.A. Herring
Keyword(s):  
Device Fabrication ◽  
High Concentration ◽  
Tem Analysis ◽  
Defect Clusters ◽  
High Fluences ◽  
Small Defect ◽  
Before And After ◽  
The Matrix ◽  
The Difference ◽  
Factor Type

Rapid thermal annealing (RTA) of ion-implanted Si is important for device fabrication. The defect structures of 2.5, 4.0, and 6.0 MeV As-implanted silicon irradiated to fluences of 2E14, 4E14, and 6E14, respectively, have been analyzed by electron diffraction both before and after RTA at 1100°C for 10 seconds. At such high fluences and energies the implanted As ions change the Si from crystalline to amorphous. Three distinct amorphous regions emerge due to the three implantation energies used (Fig. 1). The amorphous regions are separated from each other by crystalline Si (marked L1, L2, and L3 in Fig. 1) which contains a high concentration of small defect clusters. The small defect clusters were similar to what had been determined earlier as being amorphous zones since their contrast was principally of the structure-factor type that arises due to the difference in extinction distance between the matrix and damage regions.

The evolution of the microstructure of 600 Mev proton irradiated materials

1990 ◽  
Vol 48 (4) ◽  
pp. 1002-1003
Author(s):  
R. Gotthardt ◽  
A. Horsewell ◽  
F. Paschoud ◽  
S. Proennecke ◽  
M. Victoria
Keyword(s):  
Nuclear Reactions ◽  
Dislocation Loops ◽  
Defect Clusters ◽  
Weak Beam ◽  
Stacking Fault Tetrahedra ◽  
Small Defect ◽  
Sufficient Intensity ◽  
Reactor Materials ◽  
Metallic Impurities ◽  
Beam Technique

Fusion reactor materials will be damaged by an intense field of energetic neutrons. There is no neutron source of sufficient intensity at these energies available at present, so the material properties are being correlated with those obtained in irradiation with other irradiation sorces. Irradiation with 600 MeV protons produces both displacement damage and impurities due to nuclear reactions. Helium and hydrogen are produced as gaseous impurities. Other metallic impurities are also created . The main elements of the microstructure observed after irradiation in the PIREX facility, are described in the following paragraphs.A. Defect clusters at low irradiation doses: In specimens irradiated to very low doses (1021-1024 protons.m-2), so that there is no superimposition of contrast, small defect clusters have been observed by the weak beam technique. Detailed analysis of the visible contrast (>0.5 nm diameter) revealed the presence of stacking fault tetrahedra, dislocation loops and a certain number of unidentified clusters . Typical results in Cu and Au are shown in Fig. 1.

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