scholarly journals Driving energetically unfavorable dehydrogenation dynamics with plasmonics

Science ◽  
2021 ◽  
Vol 371 (6526) ◽  
pp. 280-283
Author(s):  
Katherine Sytwu ◽  
Michal Vadai ◽  
Fariah Hayee ◽  
Daniel K. Angell ◽  
Alan Dai ◽  
...  
Keyword(s):  
Optical Excitation ◽  
Chemical Transformations ◽  
Electromagnetic Enhancement ◽  
Nanoparticle Surface ◽  
Transmission Electron ◽  
Nucleation Sites ◽  
In Situ Experiments ◽  
Catalytic Sites ◽  
Dynamics Simulations

Nanoparticle surface structure and geometry generally dictate where chemical transformations occur, with higher chemical activity at sites with lower activation energies. Here, we show how optical excitation of plasmons enables spatially modified phase transformations, activating otherwise energetically unfavorable sites. We have designed a crossed-bar Au-PdHx antenna-reactor system that localizes electromagnetic enhancement away from the innately reactive PdHx nanorod tips. Using optically coupled in situ environmental transmission electron microscopy, we track the dehydrogenation of individual antenna-reactor pairs with varying optical illumination intensity, wavelength, and hydrogen pressure. Our in situ experiments show that plasmons enable new catalytic sites, including dehydrogenation at the nanorod faces. Molecular dynamics simulations confirm that these new nucleation sites are energetically unfavorable in equilibrium and only accessible through tailored plasmonic excitation.

In situ observations of electromigration induced void behavior

1995 ◽  
Vol 53 ◽  
pp. 244-245
Author(s):  
T. Marieb ◽  
J. C. Bravman ◽  
P. Flinn ◽  
D. Gardner ◽  
M. Madden
Keyword(s):  
Electron Microscopy ◽  
Void Nucleation ◽  
Plan View ◽  
Transmission Electron ◽  
Nucleation Sites ◽  
Microelectronics Industry ◽  
In Situ Observations ◽  
Backscatter Electron Detector ◽  
Voltage Scanning

Electromigration and stress voiding have been active areas of research in the microelectronics industry for many years. While accelerated testing of these phenomena has been performed for the last 25 years[1-2], only recently has the introduction of high voltage scanning electron microscopy (HVSEM) made possible in situ testing of realistic, passivated, full thickness samples at high resolution.With a combination of in situ HVSEM and post-testing transmission electron microscopy (TEM) , electromigration void nucleation sites in both normal polycrystalline and near-bamboo pure Al were investigated. The effect of the microstructure of the lines on the void motion was also studied.The HVSEM used was a slightly modified JEOL 1200 EX II scanning TEM with a backscatter electron detector placed above the sample[3]. To observe electromigration in situ the sample was heated and the line had current supplied to it to accelerate the voiding process. After testing lines were prepared for TEM by employing the plan-view wedge technique [6].

A computer-control program for TEM in situ fatigue experiments

1989 ◽  
Vol 47 ◽  
pp. 620-621
Author(s):  
Kenneth S. Vecchio ◽  
John A. Hunt
Keyword(s):  
Slow Crack Growth ◽  
Computer Control ◽  
Control Program ◽  
Video Tape ◽  
Computer Control System ◽  
Transmission Electron ◽  
In Situ Experiments ◽  
Tremendous Amount ◽  
And Control

In-situ experiments conducted within a transmission electron microscope provide the operator a unique opportunity to directly observe microstructural phenomena, such as phase transformations and dislocation-precipitate interactions, “as they happen”. However, in-situ experiments usually require a tremendous amount of experimental preparation beforehand, as well as, during the actual experiment. In most cases the researcher must operate and control several pieces of equipment simultaneously. For example, in in-situ deformation experiments, the researcher may have to not only operate the TEM, but also control the straining holder and possibly some recording system such as a video tape machine. When it comes to in-situ fatigue deformation, the experiments became even more complicated with having to control numerous loading cycles while following the slow crack growth. In this paper we will describe a new method for conducting in-situ fatigue experiments using a camputer-controlled tensile straining holder.The tensile straining holder used with computer-control system was manufactured by Philips for the Philips 300 series microscopes. It was necessary to modify the specimen stage area of this holder to work in the Philips 400 series microscopes because the distance between the optic axis and holder airlock is different than in the Philips 300 series microscopes. However, the program and interfacing can easily be modified to work with any goniometer type straining holder which uses a penrmanent magnet motor.

Observing the colloidal stability of iron oxide nanoparticlesin situ

Nanoscale ◽  
2019 ◽  
Vol 11 (27) ◽  
pp. 13098-13107 ◽  
Author(s):  
Ryan Hufschmid ◽  
Eric Teeman ◽  
B. Layla Mehdi ◽  
Kannan M. Krishnan ◽  
Nigel D. Browning
Keyword(s):  
Iron Oxide ◽  
Scanning Transmission Electron Microscopy ◽  
Colloidal Stability ◽  
Iron Oxide Nanoparticle ◽  
Nanoparticle Surface ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Liquid Cell ◽  
Oxide Nanoparticle

Iron oxide nanoparticle surface chemistry controls growth and dissolution, which are observed in real-time usingin situliquid cell Scanning Transmission Electron Microscopy (STEM).

In situ silicification of an Icelandic hot spring microbial mat: implications for microfossil formation

1995 ◽  
Vol 32 (12) ◽  
pp. 2021-2026 ◽  
Author(s):  
S. Schultze-Lam ◽  
F. G. Ferris ◽  
K. O. Konhauser ◽  
R. G. Wiese
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Hot Spring ◽  
Microbial Mat ◽  
Chloroflexus Aurantiacus ◽  
X Ray ◽  
Exceptional Preservation ◽  
Transmission Electron ◽  
Nucleation Sites

Transmission electron microscopy and energy-dispersive x-ray analysis revealed that filamentous phototrophic bacteria resembling Chloroflexus aurantiacus underwent rapid silicification in an Icelandic hot spring microbial mat. The mineralization associated with the cells occurred both extracellularly, within and on the external sheaths of the bacteria, and intracellularly, within the cytoplasm. The exceptional preservation of the bacterial sheaths is due to the presence of distinct mineral nucleation sites. This results in the production of silica casts of the bacteria, which bear a striking resemblance to microbial remains in ancient microfossil assemblages.

In-Situ Annealing of Metal Thin Films on Silicon

1981 ◽  
Vol 39 ◽  
pp. 164-165
Author(s):  
L. J. Chen ◽  
J. W. Mayer
Keyword(s):  
Thin Films ◽  
Device Fabrication ◽  
Electron Gun ◽  
Specimen Thickness ◽  
Metal Thin Films ◽  
Thin Foils ◽  
Transmission Electron ◽  
In Situ Experiments ◽  
Annealing Study

In-situ dynamical experiments in the transmission electron microscope (TEM) have long interested electron microscopists. In designing and performing the experiments, it is important to minimize the influences of the factors, which include the specimen thickness, electron beam heating, electron irradiation and specimen environments that may affect the validity of in-situ experiments. Comparisons of the results with those of other experiments are also very desirable.In microelectronic device fabrication process, it has become increasingly common to react a few hundred Å in thickness metal films with silicon substrate to form silicide contacts. Ni thin films on silicon have been chosen for in-situ annealing study since this system has been extensively investigated by Rutherford backscattering and glancing angle x-ray experiments. In-situ annealing of Co, Mo, Ti, Pd and W thin films on silicon have also been performed.Ni films, 300 and 400 Å thick, were electron gun deposited on (001) n-type silicon. Thin foils for TEM examination were chemically polished from silicon side. A JEOL 100B microscope equipped with a side entry, single tilt hot stage was used for TEM study.

Nucleation Dynamics of Water Nanodroplets

2014 ◽  
Vol 20 (2) ◽  
pp. 407-415 ◽  
Author(s):  
Dipanjan Bhattacharya ◽  
Michel Bosman ◽  
Venkata R.S.S. Mokkapati ◽  
Fong Yew Leong ◽  
Utkur Mirsaidov
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Gold Nanoparticles ◽  
Heterogeneous Nucleation ◽  
Flat Surface ◽  
Nucleation And Growth ◽  
Length Scale ◽  
Transmission Electron ◽  
Nucleation Sites

AbstractThe origin of the condensation of water begins at the nanoscale, a length-scale that is challenging to probe for liquids. In this work we directly image heterogeneous nucleation of water nanodroplets by in situ transmission electron microscopy. Using gold nanoparticles bound to a flat surface as heterogeneous nucleation sites, we observe nucleation and growth of water nanodroplets. The growth of nanodroplet radii follows the power law: R(t)~(t−t0)β, where β~0.2−0.3.

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