Luminescence Properties of Yb-Doped Inp

1993 ◽  
Vol 301 ◽  
Author(s):  
H. J. Lozykowski ◽  
A. K. Alshawa ◽  
G. Pomrenke ◽  
I. Brown
Keyword(s):  
Quantitative Agreement ◽  
Excitation Intensity ◽  
Photoluminescence Intensity ◽  
Photoluminescence Quenching ◽  
Time Resolved ◽  
Wide Range ◽  
Decay Times ◽  
Different Temperatures ◽  
First Time ◽  
Kinetics Of

ABSTRACTThe photoluminescence, time resolved spectra and kinetics of Yb implanted InP samples are studied under pulsed and CW excitations (above and below band-gap) at different temperatures and excitation intensity. The photoluminescence intensity and decay time as a function of temperature is explained by a proposed new quenching mechanism involving Fe ion. The rise and decay times depend on excitation intensity. The above experimental facts was explained using the kinetics model developed by H.J. Lozykowski [2]. The numerically simulated luminescence rise and decay times show a good quantitative agreement with experiment, over a wide range of generation rates. The electric field InP:Yb photoluminescence quenching was investigated and reported for the first time.

Kinetics of the Luminescence of Isoelectronic Rare-Earth Ions In III-V Semiconductors

1993 ◽  
Vol 301 ◽  
Author(s):  
H.J. Lozykowski
Keyword(s):  
Experimental Data ◽  
Energy Transfer ◽  
Rare Earth ◽  
Excited States ◽  
Quantitative Agreement ◽  
Host Lattice ◽  
Rare Earth Ions ◽  
Wide Range ◽  
Decay Times ◽  
Kinetics Of

ABSTRACTIn this work we have developed a model for the kinetics of the energy transfer from the host lattice to the localized core excited states of rare earth isoelectronic structured traps (REI-trap). We have derive a set of differential equations for semi-insulating semiconductor governing the kinetics of rare earth luminescence. The numerically simulated rise and decay times of luminescence show a good quantitative agreement with the experimental data obtained for InP:Yb, over a wide range of generation rates.

scholarly journals Kinetic studies of C1 and C2 Criegee intermediates with SO2 using laser flash photolysis coupled with photoionization mass spectrometry and time resolved UV absorption spectroscopy

2018 ◽  
Vol 20 (34) ◽  
pp. 22218-22227 ◽  
Author(s):  
N. U. M. Howes ◽  
Z. S. Mir ◽  
M. A. Blitz ◽  
S. Hardman ◽  
T. R. Lewis ◽  
...  
Keyword(s):  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Kinetic Studies ◽  
Laser Flash ◽  
Major Product ◽  
Time Resolved ◽  
Photoionization Mass Spectrometry ◽  
Criegee Intermediates ◽  
Wide Range ◽  
Kinetics Of

Kinetics of CH2OO + SO2 confirmed over a wide range of [SO2]. Acetaldehyde observed as a major product of the reaction of CH3CHOO + SO2.

Time resolved growth of membrane stabilized silver NPs and their catalytic activity

RSC Advances ◽  
2014 ◽  
Vol 4 (103) ◽  
pp. 59379-59386 ◽  
Author(s):  
Sabyasachi Patra ◽  
Debasis Sen ◽  
Ashok K. Pandey ◽  
J. Bahadur ◽  
S. Mazumder ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Catalytic Activity ◽  
Growth Kinetics ◽  
Nanocomposite Membranes ◽  
Time Resolved ◽  
Catalytic Application ◽  
Silver Nps ◽  
First Time ◽  
Kinetics Of

Growth kinetics of membrane stabilized silver nanoparticles have been studied for the first time with time resolved in situ SAXS. The catalytic application of nanocomposite membranes thus formed has also been explored.

scholarly journals Prevalence of Anti-Varicella-Zoster Virus Antibodies in French Infants under 15 Months of Age

2009 ◽  
Vol 16 (4) ◽  
pp. 484-487 ◽  
Author(s):  
Didier Pinquier ◽  
Arnaud Gagneur ◽  
Laurent Balu ◽  
Olivier Brissaud ◽  
Christèle Gras Le Guen ◽  
...  
Keyword(s):  
Varicella Zoster Virus ◽  
Pediatric Emergency ◽  
Rapid Decline ◽  
Time Resolved ◽  
Varicella Zoster ◽  
Emergency Units ◽  
History Of ◽  
Low Levels ◽  
First Time ◽  
Kinetics Of

ABSTRACT Varicella is a widespread disease of childhood resulting from primary infection with varicella-zoster virus (VZV). The objective of this study was to determine the kinetics of the decline of maternal anti-VZV antibodies in French infants between birth and the age of 15 months in order to estimate the duration of passively acquired maternal anti-VZV immunoglobulin G (IgG). This prospective multicenter study was conducted between October 2005 and January 2007 in the pediatric wards and/or pediatric emergency units of seven French hospitals scattered throughout the country. The level of anti-VZV IgG antibodies in serum was measured by a time-resolved fluorescence immunoassay (TRFIA) (the threshold considered positive is 150 mIU/ml). A total of 345 infants were included. Seventy-seven percent of mothers reported a history of varicella. A rapid decline in the prevalence of anti-VZV antibodies was observed during the first few months of life, with the mean antibody titer decreasing from 536 mIU/ml at birth and through 1 month to below the 150-mIU/ml threshold at 3 to 4 months. The half-life of passively acquired maternal immunoglobulins was around 6 weeks. Based on a large number of subjects, this study clearly demonstrated, for the first time in France, high levels of passively acquired maternal antibodies during the neonatal period, and it allowed us to estimate the duration of passively acquired maternal anti-VZV IgG in French infants. After 4 to 5 months, infants had very low levels of maternal anti-VZV IgG, below the 150-mIU/ml cutoff of the VZV IgG TRFIA.

scholarly journals HETERO TRANSITIONS BASED ON - TlGaSe2 - - CuInSe2

2021 ◽  
Author(s):  
A.Ch. Matiyev ◽  
R.T. Uspazhiev
Keyword(s):  
Relaxation Time ◽  
Current Voltage ◽  
Wide Range ◽  
The Law ◽  
First Time ◽  
Kinetics Of

The current-voltage and lux-ampere characteristics, as well as the photovoltage spectra and the lux dependence of the photovoltage in the gate and photodiode modes of the p-TlGaSe2 - p-CuInSe2 heterojunction obtained for the first time are studied. It was found that this heterostructure has a pronounced diode character. The I - V characteristic of the structure under study is characterized by the fact that at low voltages it obeys well the law I ~ exp (eU / βkT). The photovoltage spectrum covers a wide range of wavelengths (0.55 - 1.85 µm). In this case, pronounced maxima are observed at λ = 0.59 and λ = 0.95 μm. The relaxation time τ determined from the kinetics of the photo-voltage in the valve mode is ~ 20 μs.

Na3Sm(PO4)2: (3+1)-dimensional commensurately modulated structure model and photoluminescence properties

2019 ◽  
Vol 234 (5) ◽  
pp. 281-289 ◽  
Author(s):  
Rui-Juan Zhang ◽  
Dan Zhao ◽  
Qiu Zhong ◽  
Ya-Li Xue ◽  
Guang-Xu Huang
Keyword(s):  
Structure Model ◽  
X Ray Diffraction ◽  
Modulated Structure ◽  
Characteristic Emission ◽  
Wide Range ◽  
Different Temperatures ◽  
Superspace Formalism ◽  
First Time ◽  
Uv Excitation ◽  
Orange Color

Abstract For the first time, we determined the detailed crystal structure of Na3Sm(PO4)2 using single crystal X-ray diffraction and established the commensurately modulated structure model using the superspace formalism. The structure adopts a (3+1)-dimensional superspace group Pca21(0β0)000 with the modulation vector q=1/3b*. At the same time, the photoluminescent properties of Na3Sm(PO4)2 sintered at different temperatures between 800 and 1200°C were studied. Under near-UV excitation (402 nm), Na3Sm(PO4)2 shows intense characteristic emission bands of Sm3+ (561, 596, 642 nm) with the CIE coordinate of (0.5709, 0.4282), corresponding to orange color. The excitation spectrum covers a wide range from 350 nm to 470 nm, which indicates that Na3Sm(PO4)2 can be efficiently activated by near-UV or visuable LED ship.

Research of the kinetics of synthesis and peculiarities of solid-phase formation of mullite

2021 ◽  
Vol 1 (7) ◽  
pp. 16-20
Author(s):  
A. M. Eminov ◽  
Z. R. Kadyrova ◽  
Azizjon A. Eminov ◽  
Afzal A. Eminov ◽  
I. R. Bayjanov
Keyword(s):  
Heat Treatment ◽  
Aluminum Oxide ◽  
Phase Formation ◽  
Firing Temperature ◽  
Solid Phase ◽  
Different Temperatures ◽  
First Time ◽  
Kinetics Of

The article presents the production of ash silica during heat treatment and the schemes of modification transformation at different temperatures. On the basis of ash silica and aluminum oxide in the alumina‒silica system, mullite 3Al2O3·2SiO2 was synthesized for the first time at a relatively low firing temperature.

scholarly journals Investigation on photoluminescence quenching of CdSe/ZnS quantum dots by organic charge transporting materials

2015 ◽  
Vol 33 (4) ◽  
pp. 709-713 ◽  
Author(s):  
Qu Yuqiu ◽  
Zhang Liuyang ◽  
An Limin ◽  
Wei Hong
Keyword(s):  
Quantum Dots ◽  
Oxidation Potential ◽  
Core Shell ◽  
Photoluminescence Intensity ◽  
Dynamic Quenching ◽  
Photoluminescence Quenching ◽  
Time Resolved ◽  
Quenching Efficiency ◽  
Hole Transporting ◽  
Time Resolved Photoluminescence

AbstractThe effect of different organic charge transporting materials on the photoluminescence of CdSe/ZnS core/shell quantum dots has been studied by means of steady-state and time-resolved photoluminescence spectroscopy. With an increase in concentration of the organic charge transporting material in the quantum dots solutions, the photoluminescence intensity of CdSe/ZnS quantum dots was quenched greatly and the fluorescence lifetime was shortened gradually. The quenching efficiency of CdSe/ZnS core/shell quantum dots decreased with increasing the oxidation potential of organic charge transporting materials. Based on the analysis, two pathways in the photoluminescence quenching process have been defined: static quenching and dynamic quenching. The dynamic quenching is correlated with hole transporting from quantum dots to the charge transporting materials.

Kinetics of Intrinsic and Dopant-Enhanced Solid Phase Epitaxy in Buried Amorphous Si Layers

1996 ◽  
Vol 439 ◽  
Author(s):  
J. C. McCallum
Keyword(s):  
Ion Implantation ◽  
Dopant Concentration ◽  
Solid Phase ◽  
Solid Phase Epitaxy ◽  
Entire Concentration Range ◽  
Time Resolved ◽  
Amorphous Si ◽  
First Time ◽  
Kinetics Of ◽  
Suitable Environment

AbstractThe kinetics of intrinsic and dopant-enhanced solid phase epitaxy (SPE) have been measured in buried amorphous Si (a-Si) layers produced by ion implantation. Buried a-Si layers formed by self-ion implantation provide a suitable environment for studies of the intrinsic growth kinetics of amorphous Si, free from the rate-retarding effects of H. For the first time, dopant-enhanced SPE rates have been measured under these H-free conditions. Buried a-Si layers containing uniform As concentration profiles ranging from 1–16.1 × 1019 As.cm−3 were produced by multiple-energy ion implantation and time resolved reflectivity was used to measure SPE rates over the temperature range 480–660°C. In contrast to earlier studies, the dopant-enhanced SPE rate is found to depend linearly on the As concentration over the entire concentration range measured. The SPE rate can be expressed in the form, v/vi(T) = 1 + N/[No exp(-ΔE/kT)], where vi(T) is the intrinsic SPE rate, N is the dopant concentration and No = 1.2 × 1021 cm−3, ΔE = 0.21 eV.

Influence of Electrolytes and Humic Acid on Aggregation Behavior of C60 Nanoparticles in Aquatic System

2013 ◽  
Vol 448-453 ◽  
pp. 48-51
Author(s):  
Hua Fang ◽  
Bing Bing Shen ◽  
Yu Xin Sun ◽  
Yuan Wang ◽  
Ji Lai Lu
Keyword(s):  
Humic Acid ◽  
Colloidal Stability ◽  
Dlvo Theory ◽  
Aquatic Environments ◽  
Aggregation Kinetics ◽  
Time Resolved ◽  
Diffusion Limited ◽  
Wide Range ◽  
Kinetics Of ◽  
And Diffusion

The aggregation kinetics of C60 nanoparticles have been investigated over a wide range of monovalent and divalent electrolyte concentrations by employing time-resolved dynamic light scattering (DLS). The results showed that the presence of electrolyte made a dramatic decrease in the surface zeta potential and increase in the particle size. The aggregation kinetics of C60 nanoparticles exhibited reaction-limited and diffusion-limited regimes, which was found to be consistent with the classic Derjaguin-Landau-Verwey-Overbeek (DLVO) theory of colloidal stability. The critical coagulation concentration (CCC) values of C60 nanoparticles were estimated as 321mM Na+, 295mM K+, 9.6mM Ca2+and 6.7mM Mg2+, which were far higher than the electrolyte concentrations in natural water. The enhanced C60 stability in the presence of humic acid was attributable to steric repulsion. Therefore C60 nanoparticles can be relatively stable in typical aquatic environments.

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