scholarly journals Spatiotemporal dynamics of nanowire growth in a microfluidic reactor

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Mazen Erfan ◽  
Martine Gnambodoe-Capochichi ◽  
Yasser M. Sabry ◽  
Diaa Khalil ◽  
Yamin Leprince-Wang ◽  
...  
Keyword(s):  
Synergetic Effect ◽  
Growth Dynamics ◽  
Time Resolved ◽  
Oxide Nanowires ◽  
Experimental Platform ◽  
Spatially Resolved ◽  
Microfluidic Reactor ◽  
Microfluidic Chamber ◽  
Confined Environment

AbstractCo-integration of nanomaterials into microdevices poses several technological challenges and presents numerous scientific opportunities that have been addressed in this paper by integrating zinc oxide nanowires (ZnO-NWs) into a microfluidic chamber. In addition to the applications of these combined materials, this work focuses on the study of the growth dynamics and uniformity of nanomaterials in a tiny microfluidic reactor environment. A unique experimental platform was built through the integration of a noninvasive optical characterization technique with the microfluidic reactor. This platform allowed the unprecedented demonstration of time-resolved and spatially resolved monitoring of the in situ growth of NWs, in which the chemicals were continuously fed into the microfluidic reactor. The platform was also used to assess the uniformity of NWs grown quickly in a 10-mm-wide microchamber, which was intentionally chosen to be 20 times wider than those used in previous attempts because it can accommodate applications requiring a large surface of interaction while still taking advantage of submillimeter height. Further observations included the effects of varying the flow rate on the NW diameter and length in addition to a synergetic effect of continuous renewal of the growth solution and the confined environment of the chemical reaction.

Direct Measurement of Cw Laser-Induced Crystal Growth Dynamics by Time-Resolved Optical Reflectivity

1980 ◽  
Vol 1 ◽  
Author(s):  
G.L. Olson ◽  
S.A. Kokorowski ◽  
J.A. Roth ◽  
L.D. Hess
Keyword(s):  
Crystal Growth ◽  
Solid Phase ◽  
Growth Dynamics ◽  
Time Resolved ◽  
Laser Method ◽  
Optical Reflectivity ◽  
Spatially Resolved ◽  
Use Of Time ◽  
Cw Laser

ABSTRACTWe report the use of time-resolved optical reflectivity to directly monitor the dynamics of cw laser-induced solid phase epitaxy (SPE) of thin films. This in situ measurement technique utilizes optical interference effects between light reflected from the surface of a sample and from an advancing interface to provide continuous temporal and spatial resolution of crystal growth processes. SPE growth rates of ionimplanted films which are five orders of magnitude faster than previously observed can be induced and accurately measured with the laser method. Arsenic enhances the SPE rate, and spatially resolved measurements show that the growth rate for arsenic implanted films varies in accordance with the ionimplantation profile. Results are reported for silicon selfimplanted samples with and without subsequent arsenic ion implantation, and for silicon samples directly implanted with arsenic.

Zinc-oxide nanowires growth in-situ in microfluidic chamber

2019 ◽  
Author(s):  
Mazen Erfan ◽  
Martine Gnambodoe-Capochichi ◽  
Marie Le Pivert ◽  
Frédéric Marty ◽  
Yasser M. Sabry ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Zinc Oxide Nanowires ◽  
Oxide Nanowires ◽  
Microfluidic Chamber ◽  
Nanowires Growth

Real-time optical monitoring of zinc-oxide nanowires in-situ growth within a microfluidic chamber

2020 ◽  
Author(s):  
Mazen Erfan ◽  
Lan Gao ◽  
Marie Le Pivert ◽  
Martine Gnambodoe-Capochichi ◽  
Yasser M. Sabry ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Real Time ◽  
Optical Monitoring ◽  
In Situ Growth ◽  
Zinc Oxide Nanowires ◽  
Oxide Nanowires ◽  
Microfluidic Chamber

Emerging techniques for the in situ analysis of reaction intermediates on photo-electrochemical interfaces

2015 ◽  
Vol 7 (17) ◽  
pp. 7029-7041 ◽  
Author(s):  
B. H. Simpson ◽  
J. Rodríguez-López
Keyword(s):  
In Situ Analysis ◽  
Semiconductor Surface ◽  
Reaction Intermediates ◽  
Time Resolved ◽  
Spatially Resolved ◽  
Electrochemical Interfaces

We offer a perspective on how new in situ methods enable the chemically-sensitive, time-resolved and spatially-resolved exploration of semiconductor surface photo(electro)chemistry.

Electron Channeling Patterns

1977 ◽  
Vol 35 ◽  
pp. 12-13
Author(s):  
David C. Joy
Keyword(s):  
Electron Diffraction ◽  
Incidence Angle ◽  
Photographic Plate ◽  
Diffraction Effect ◽  
Angle Of Incidence ◽  
Bulk Single Crystal ◽  
Time Resolved ◽  
Electron Channeling ◽  
Spatially Resolved ◽  
Large Bulk

Electron channeling patterns (ECP) were first found by Coates (1967) while observing a large bulk, single crystal of silicon in a scanning electron microscope. The geometric pattern visible was shown to be produced as a result of the changes in the angle of incidence, between the beam and the specimen surface normal, which occur when the sample is examined at low magnification (Booker, Shaw, Whelan and Hirsch 1967).A conventional electron diffraction pattern consists of an angularly resolved intensity distribution in space which may be directly viewed on a fluorescent screen or recorded on a photographic plate. An ECP, on the other hand, is produced as the result of changes in the signal collected by a suitable electron detector as the incidence angle is varied. If an integrating detector is used, or if the beam traverses the surface at a fixed angle, then no channeling contrast will be observed. The ECP is thus a time resolved electron diffraction effect. It can therefore be related to spatially resolved diffraction phenomena by an application of the concepts of reciprocity (Cowley 1969).

FT-IR microspectroscopic analysis of diseased white matter brain tissues

1995 ◽  
Vol 53 ◽  
pp. 968-969
Author(s):  
Steven M. Le Vine ◽  
David L. Wetzel
Keyword(s):  
White Matter ◽  
Gray Matter ◽  
Twitcher Mouse ◽  
Grid Pattern ◽  
Marked Contrast ◽  
Spatially Resolved ◽  
Ft Ir ◽  
Ir Microspectroscopy ◽  
Chemical Evidence

In situ FT-IR microspectroscopy has allowed spatially resolved interrogation of different parts of brain tissue. In previous work the spectrrscopic features of normal barin tissue were characterized. The white matter, gray matter and basal ganglia were mapped from appropriate peak area measurements from spectra obtained in a grid pattern. Bands prevalent in white matter were mostly associated with the lipid. These included 2927 and 1469 cm-1 due to CH2 as well as carbonyl at 1740 cm-1. Also 1235 and 1085 cm-1 due to phospholipid and galactocerebroside, respectively (Figs 1and2). Localized chemical changes in the white matter as a result of white matter diseases have been studied. This involved the documentation of localized chemical evidence of demyelination in shiverer mice in which the spectra of white matter lacked the marked contrast between it and gray matter exhibited in the white matter of normal mice (Fig. 3).The twitcher mouse, a model of Krabbe’s desease, was also studied. The purpose in this case was to look for a localized build-up of psychosine in the white matter caused by deficiencies in the enzyme responsible for its breakdown under normal conditions.

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.

Monitoring Polymer-Assisted Mechanochemical Cocrystallisation Through in Situ X-Ray Powder Diffraction

2020 ◽  
Author(s):  
Luzia S. Germann ◽  
Sebastian T. Emmerling ◽  
Manuel Wilke ◽  
Robert E. Dinnebier ◽  
Mariarosa Moneghini ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Powder Diffraction ◽  
Reaction Rate ◽  
Polymer Additives ◽  
Time Resolved ◽  
X Ray

Time-resolved mechanochemical cocrystallisation studies have so-far focused solely on neat and liquid-assisted grinding. Here, we report the monitoring of polymer-assisted grinding reactions using <i>in situ</i> X-ray powder diffraction, revealing that reaction rate is almost double compared to neat grinding and independent of the molecular weight and amount of used polymer additives.<br>

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