scholarly journals Metal-semiconductor nanoheterostructures with an AlGaN quantum well and in-situ formed surface Al nanoislands

2018 ◽  
Vol 52 (5) ◽  
pp. 515
Author(s):  
E.A. Evropeytsev ◽  
A.N. Semenov ◽  
D.V. Nechaev ◽  
V.N. Jmerik ◽  
V.Kh. Kaibyshev ◽  
...  
Keyword(s):  
Quantum Well ◽  
Maximum Density ◽  
Metal Particles ◽  
Decay Kinetics ◽  
Time Resolved ◽  
Sapphire Substrates ◽  
Photoluminescence Lifetime ◽  
Time Resolved Photoluminescence ◽  
Kinetics Of

AbstractWe report on fabrication and studies of composite heterostuctures consisting of an Al_0.55Ga_0.45N/A_l0.8Ga_0.2N quantum well and surface Al nanoislands, grown by plasma-assisted molecularbeam epitaxy on c-sapphire substrates. The influence of a substrate temperature varied between 320 and 700ºC on the size and density of the deposited Al nanoislands is evaluated. The effect of Al nanoislands on decay kinetics of the quantum well middle-ultraviolet photoluminescence has been investigated by time resolved photoluminescence. The samples with the maximum density of Al nanoislands of 10^8 cm^–2 and lateral dimensions in the range of 100–500 nm demonstrated shortening of the photoluminescence lifetime, induced by interaction of the emitting quantum well and the plasmonic metal particles.

scholarly journals Фотолюминесценция с временным разрешением наноструктур InGaAs различной квантовой размерности

2019 ◽  
Vol 53 (11) ◽  
pp. 1520
Author(s):  
А.М. Надточий ◽  
С.А. Минтаиров ◽  
Н.А. Калюжный ◽  
М.В. Максимов ◽  
Д.А. Санников ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Well ◽  
Single Photon ◽  
Photon Counting ◽  
Dimensional Structure ◽  
Time Resolved ◽  
Single Photon Counting ◽  
Gaas Substrates ◽  
Photoluminescence Lifetime ◽  
Time Resolved Photoluminescence

By using time-correlated single-photon counting time-resolved photoluminescence of quantum-sized heterostructures of different dimensionality was investigated. InGaAs quantum dots, quantum well, and transitionally-dimensional structure — quantum well-dots were grown on GaAs substrates. It was observed, that photoluminescence decay strongly depends on structure dimensionality resulting in decay value of 6,7, and more than 20 ns for quantum dots, well-dots and well, respectively. As we believe localization centers in heterostructures may be responsible for such shortening of photoluminescence lifetime.

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.

In situ Time-Resolved Small-Angle X-ray Scattering Reveals the Formation Kinetics of Polyelectrolyte Complex Micelles

2019 ◽  
Author(s):  
Hao Wu ◽  
Jeffrey Ting ◽  
Siqi Meng ◽  
Matthew Tirrell
Keyword(s):  
Small Angle ◽  
Self Assembly ◽  
Electrostatic Interactions ◽  
Polyelectrolyte Complex ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
Kinetics Of ◽  
Ray Scattering

We have directly observed the <i>in situ</i> self-assembly kinetics of polyelectrolyte complex (PEC) micelles by synchrotron time-resolved small-angle X-ray scattering, equipped with a stopped-flow device that provides millisecond temporal resolution. This work has elucidated one general kinetic pathway for the process of PEC micelle formation, which provides useful physical insights for increasing our fundamental understanding of complexation and self-assembly dynamics driven by electrostatic interactions that occur on ultrafast timescales.

scholarly journals In situ structural kinetics of picosecond laser-induced heating and fragmentation of colloidal gold spheres

2020 ◽  
Vol 22 (9) ◽  
pp. 4993-5001 ◽  
Author(s):  
Anna Rosa Ziefuss ◽  
Stefan Reich ◽  
Sven Reichenberger ◽  
Matteo Levantino ◽  
Anton Plech
Keyword(s):  
Colloidal Gold ◽  
Picosecond Laser ◽  
Time Resolved ◽  
Gold Colloids ◽  
X Ray ◽  
X Ray Scattering ◽  
Kinetics Of ◽  
Ray Scattering

The structural and energetic pathway of picosecond laser fragmentation of gold colloids has been clarified by time-resolved X-ray scattering.

scholarly journals Electric Field Distribution in strained p-i-n GaN/InGaN multiple quantum well structures.

1999 ◽  
Vol 4 (1) ◽  
Author(s):  
A.N. Cartwright ◽  
Paul M. Sweeney ◽  
Thomas Prunty ◽  
David P. Bour ◽  
Michael Kneissl
Keyword(s):  
Quantum Well ◽  
Electric Field Distribution ◽  
Theoretical Calculations ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
Time Resolved ◽  
Quantum Well Structures ◽  
Piezoelectric Field ◽  
Piezoelectric Fields ◽  
Time Resolved Photoluminescence

The presence of piezoelectric fields within p-i-n GaN/InGaN multiple quantum well structures is discussed. Time integrated and time-resolved photoluminescence measurements and theoretical calculations of the effect of these fields is presented. Furthermore, a description of how these fields influence the carrier dynamics and a discussion of how the piezoelectric field effects the design of GaN/InGaN devices is presented.

Kinetics of Multi-Step Redox Processes by Time-Resolved In Situ X-ray Diffraction

2016 ◽  
Vol 88 (11) ◽  
pp. 1684-1692 ◽  
Author(s):  
Lukas C. Buelens ◽  
Vladimir V. Galvita ◽  
Hilde Poelman ◽  
Christophe Detavernier ◽  
Guy B. Marin
Keyword(s):  
Redox Processes ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Kinetics Of

Decay Kinetics of Cluster-Beam-Deposited Metal Particles

2012 ◽  
Vol 116 (36) ◽  
pp. 19327-19334 ◽  
Author(s):  
Niklas Grönhagen ◽  
Tommi T. Järvi ◽  
Natalie Miroslawski ◽  
Heinz Hövel ◽  
Michael Moseler
Keyword(s):  
Metal Particles ◽  
Cluster Beam ◽  
Decay Kinetics ◽  
Deposited Metal ◽  
Kinetics Of

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.

Time‐resolved photoluminescence study on AlxGa1−xAs spontaneous vertical quantum well structures

1996 ◽  
Vol 68 (23) ◽  
pp. 3221-3223 ◽  
Author(s):  
Noritaka Usami ◽  
Wugen Pan ◽  
Hiroyuki Yaguchi ◽  
Ryoichi Ito ◽  
Kentaro Onabe ◽  
...  
Keyword(s):  
Quantum Well ◽  
Time Resolved ◽  
Quantum Well Structures ◽  
Photoluminescence Study ◽  
Time Resolved Photoluminescence
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