scholarly journals Er3+ Photoluminescence Properties of Erbium-doped Si/SiO2 Superlattices with sub-nm Thin Si Layers

2000 ◽  
Vol 638 ◽  
Author(s):  
Yong Ho Ha ◽  
Sehun Kim ◽  
Dae Won Moon ◽  
Ji-Hong Jhe ◽  
Jung H. Shin
Keyword(s):  
Temperature Dependence ◽  
Layer Thickness ◽  
Luminescence Intensity ◽  
Luminescence Properties ◽  
Photoluminescence Properties ◽  
Time Resolved ◽  
Excitation Rate ◽  
Erbium Doped ◽  
Order Of Magnitude ◽  
Er Doped

AbstractThe effect of varying the Si layer thickness on the Er3+ photoluminescence properties of Er-doped Si/SiO2 superlattice is investigated. We find that as the Si layer thickness is reduced from 3.6 nm down to a monolayer of Si, the Er3+ luminescence intensity increases by over an order of magnitude. Temperature dependence of the Er3+ luminescence intensity and time-resolved measurement of Er3+ luminescence intensity identify the increase in the excitation rate as the likely cause for such an increase, and underscore the importance of the Si/SiO2 interface in determining the Er3+ luminescence properties.

Long Luminescence Lifetime of 1.54 μ m Er3+ Luminescence from Erbium Doped Silicon Rich Silicon Oxide and its Origin

1998 ◽  
Vol 536 ◽  
Author(s):  
Se-Young Seo ◽  
Jung H. Shin ◽  
Choochon Lee
Keyword(s):  
Room Temperature ◽  
Radiative Decay ◽  
Silicon Oxide ◽  
Silicon Nanoclusters ◽  
Excitation Rate ◽  
Carrier Recombination ◽  
Erbium Doped ◽  
Doped Silicon ◽  
Almost All ◽  
Er Doped

AbstractThe photoluminescent properties of erbium doped silicon rich silicon oxide (SRSO) is investigated. The silicon content of SRSO was varied from 43 to 33 at. % and Er concentration was 0.4–0.7 at. % in all cases. We observe strong 1.54 μ m luminescence due to 4I13/2⇒4I15/2 Er3+ 4f transition, excited via energy transfer from carrier recombination in silicon nanoclusters to Er 4f shells. The luminescent lifetimes at the room temperature are found to be 4–7 msec, which is longer than that reported from Er in any semiconducting host material, and comparable to that of Er doped SiO2 and A12O3. The dependence of the Er3+ luminescent intensities and lifetimes on temperature, pump power and on background illumination shows that by using SRSO, almost all non-radiative decay paths of excited Er3+ can be effectively suppressed, and that such suppression is more important than increasing excitation rate of Er3+. A planar waveguide using Er doped SRSO is also demonstrated.

UPS of a-Si:H: What is the energy of the Er 4f states?

2000 ◽  
Vol 609 ◽  
Author(s):  
Leandro R. Tessler ◽  
Cínthia Piamonteze ◽  
Ana Carola Iniguez ◽  
Abner de Siervo ◽  
Richard Landers ◽  
...  
Keyword(s):  
Binding Energy ◽  
Excitation Energy ◽  
Cross Section ◽  
Energy Gap ◽  
Valence States ◽  
Erbium Doped ◽  
Order Of Magnitude ◽  
Synchrotron Light ◽  
The Cross ◽  
Er Doped

ABSTRACTOne very important problem concerning erbium-doped silicon is the electronic structure of the Er3+ impurities. In particular, it is still not clear if the 4f levels can be treated as frozen core levels or their overlap with s and p states of their neighbors must be considered explicitly. For crystalline Si, the 4f levels have been supposed to be anywhere between 20 eV below the valence band and within the energy gap. In this paper we report on the first ultraviolet photoemission spectroscopy (UPS) measurements on Er-doped a-Si:H. Samples of a-Si:H<Er> with different Er contents (up to 1 at. % Er) were prepared by co-sputtering from a Si target partially covered with metallic Er platelets. In order to enhance the Er states relative to the Si and H states, the excitation energy was tuned between 40 and 140 eV with a synchrotron light source. At 140 eV excitation energy the cross-section of the Er 4f and 5p states is more than an order of magnitude higher than the cross section of the Si 3s or 3p states. As the Er concentration increases, a shoulder and then a peak appears at 10.0±0.5 eV binding energy. The intensity and width of this peak is well correlated with the Er concentration, and with the Er 5p and 5p½ levels at 26 and 32 eV binding energy, respectively. We attribute the peak at 10.0±0.5 eV binding energy to the Er 4f level. These are the only occupied states that can be related to the presence of Er, indicating that these levels are not valence states and consequently can be treated as frozen core levels.

On the Electrical and Photoluminescence Properties of Erbium Doped ZnO Thin Film

2012 ◽  
Vol 1471 ◽  
Author(s):  
Liang-Chiun Chao ◽  
Chung-Chi Liau ◽  
Wan-Chun Chang
Keyword(s):  
Carrier Concentration ◽  
Room Temperature ◽  
Ion Beam ◽  
Processing Conditions ◽  
Photoluminescence Properties ◽  
Dual Beam ◽  
Erbium Doped ◽  
Doped Zno ◽  
Er Doped ◽  
Ion Beam Sputter Deposition

ABSTRACTEr doped ZnO (Er:ZnO) thin films with Er concentration from 0.1 to 3.6 at. % were prepared by dual beam ion beam sputter deposition at room temperature. Experimental results show that as Er concentration increases from 0.1 to 1.1 at. %, the resistivity of the as-deposited Er:ZnO film decreases from 560 Ω·cm to a minimum of 0.23 Ω·cm, while further increasing Er concentration to 3.6 at. % results in increase of the resistivity to 4.2 kΩ·cm. The as-deposited Er:ZnO with Er concentration of 1.1 at.% also exhibits the highest carrier concentration of 2.3×1019 cm-3. None of the as-deposited Er:ZnO films show 1.5 μm emission without post-growth annealing. Er:ZnO film with Er concentration at 0.5~1.1 at.% shows the strongest 1.5 μm emission after annealing at 700 ~ 900°C, while all the Er:ZnO film becomes semi-insulating after annealing. The discrepancy between the processing conditions for optimized carrier concentration and optimized optically activated Er ions may due to the formation of the pseudo-octahedral structure after annealing that favors the 1.5 μm emission.

Exciton-mediated excitation of Er3+ in Erbium-doped silicon rich silicon oxide

2000 ◽  
Vol 638 ◽  
Author(s):  
Se-Young Seo ◽  
Jung H. Shin
Keyword(s):  
Silicon Oxide ◽  
Electron Cyclotron Resonance ◽  
Chemical Vapor ◽  
Excitation Power ◽  
Time Resolved ◽  
Modeling And Analysis ◽  
Visible Luminescence ◽  
Erbium Doped ◽  
Doped Silicon ◽  
Er Doped

AbstractExciton-mediated excitation of Er3+ in erbium doped silicon rich silicon oxide (SRSO) is investigated. Er-doped SRSO films were fabricated by electron cyclotron-resonance plasmaenhanced chemical vapor deposition of Er-doped SiOx (x < 2) using SiH4 and O2 as source gases and co-sputtering of Er, followed by an anneal at 950 °C. Very weak visible luminescence from Si nanocluster relative to Er3+ luminescence were observed, indicating a very efficient excitation of Er3+ ions by Si nanoclusters. From detailed modeling and analysis of time-resolved Er3+ luminescence as the excitation duration and excitation power, we conclude that exciton-erbium coupling is dominant over exciton-nanocluster. The results are consistent with the proposal that the luminescent Er3+ ions are located predominantly in the SiO2 layer.

Crystal Phase, Shape and Luminescence Properties of LaPO4:Eu3+ Nanocrystals

2008 ◽  
Vol 8 (7) ◽  
pp. 3458-3464 ◽  
Author(s):  
Pushpal Ghosh ◽  
Amitava Patra
Keyword(s):  
Growth Mechanism ◽  
Decay Time ◽  
Luminescence Intensity ◽  
Monoclinic Phase ◽  
Photoluminescence Property ◽  
Oriented Attachment ◽  
Crystal Phase ◽  
Luminescence Properties ◽  
Photoluminescence Properties ◽  
Drastic Increase

We demonstrated the change of shape and crystal phase of LaPO4:Eu3+ nanomaterials by tuning the temperature of heating. The mechanism related to morphology control of LaPO4:Eu nanorods/nanoparticles are proposed and discussed. We describe the "oriented attachment" growth mechanism for nanorod-to-nanoparticles transformation with increasing the temperature of heating. It is found that the photoluminescence properties of LaPO4:Eu3+ nanostructures are sensitive to the crystal phase and shape. The drastic increase in luminescence intensity (12 times) and decay time increases from 2.66 to 3.34 ms with changing the shape (nanorod to nanoparticle) and crystal phase (hexagonal to monoclinic phase) for the samples prepared by emulsion based method. Our analysis suggests that the manipulation of the photoluminescence property can be done by changing the crystal phase of nanomaterials.

Exciton dynamics in thick GaN MOVPE epilayers deposited on sapphire.

1997 ◽  
Vol 2 ◽  
Author(s):  
J. Allègre ◽  
P. Lefebvre ◽  
J. Camassel ◽  
B. Beaumont ◽  
Pierre Gibart
Keyword(s):  
Layer Thickness ◽  
Buffer Layers ◽  
Rate Equations ◽  
Time Resolved ◽  
Versus Layer ◽  
Level Model ◽  
Shallow Impurities ◽  
Aln Buffer ◽  
Time Resolved Photoluminescence

Time-resolved photoluminescence spectra have been recorded on three GaN epitaxial layers of thickness 2.5 μm, 7 μm and 16 μm, at various temperatures ranging from 8K to 300K. The layers were deposited by MOVPE on (0001) sapphire substrates with standard AlN buffer layers. To achieve good homogeneities, the growth was in-situ monitored by laser reflectometry. All GaN layers showed sharp excitonic peaks in cw PL and three excitonic contributions were seen by reflectivity. The recombination dynamics of excitons depends strongly upon the layer thickness. For the thinnest layer, exponential decays with τ ~ 35 ps have been measured for both XA and XB free excitons. For the thickest layer, the decay becomes biexponential with τ1 ~ 80 ps and τ2 ~ 250 ps. These values are preserved up to room temperature. By solving coupled rate equations in a four-level model, this evolution is interpreted in terms of the reduction of density of both shallow impurities and deep traps, versus layer thickness, roughly following a L−1 law.

scholarly journals Helmet Phthalocyaninato Iron Complex as a Primary Drier for Alkyd Paints

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1220
Author(s):  
Jan Honzíček ◽  
Eliška Matušková ◽  
Štěpán Voneš ◽  
Jaromír Vinklárek
Keyword(s):  
Catalytic Performance ◽  
Mechanical Tests ◽  
Iron Complex ◽  
Kinetic Measurements ◽  
Time Resolved ◽  
Strong Activity ◽  
Vis Spectroscopy ◽  
Order Of Magnitude ◽  
Transparent Coatings ◽  
Time Resolved Infrared Spectroscopy

This study describes the catalytic performance of an iron(III) complex bearing a phthalocyaninato-like ligand in two solvent-borne and two high-solid alkyd binders. Standardized mechanical tests revealed strong activity, which appeared in particular cases at concentrations about one order of magnitude lower than in the case of cobalt(II) 2-ethylhexanoate, widespread used in paint-producing industry. The effect of the iron(III) compound on autoxidation process, responsible for alkyd curing, was quantified by kinetic measurements by time-resolved infrared spectroscopy and compared with several primary driers. Effect of the drier concentration on coloration of transparent coatings was determined by UV–Vis spectroscopy.

Temperature Dependence of Luminescence Intensity of Tb3+ Complexes

1970 ◽  
Vol 52 (9) ◽  
pp. 4912-4914 ◽  
Author(s):  
R. W. Harrigan ◽  
G. A. Crosby
Keyword(s):  
Temperature Dependence ◽  
Luminescence Intensity

Temperature dependence of time-resolved photoluminescence of bound excitons in CuInS2 crystals

2005 ◽  
Vol 480-481 ◽  
pp. 283-285 ◽  
Author(s):  
K. Wakita ◽  
K. Nishi ◽  
Y. Ohta ◽  
T. Onishi
Keyword(s):  
Temperature Dependence ◽  
Time Resolved ◽  
Time Resolved Photoluminescence
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