Ionization-induced effects in amorphous apatite at elevated temperatures

2008 ◽  
Vol 23 (4) ◽  
pp. 962-967 ◽  
Author(s):  
In-Tae Bae ◽  
Yanwen Zhang ◽  
William J. Weber ◽  
Manabu Ishimaru ◽  
Yoshihiko Hirotsu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Beam ◽  
Elevated Temperatures ◽  
Amorphous Material ◽  
Transmission Electron ◽  
Oxygen Migration ◽  
Structural Contrast

Electron-beam-induced effects in preamorphized Sr2Nd8(SiO4)6O2 were investigated in situ using transmission electron microscopy with 200-keV electrons at temperatures ranging from 380 to 780 K. Within the electron-irradiated area, epitaxial recrystallization was observed from the amorphous/crystalline interface toward the surface, with the rate of recrystallization increasing as temperature increased from 380 to 580 K. Structural contrast features (i.e., O deficient amorphous material), as well as recrystallization, were observed outside of the irradiation area at temperatures from 680 to 780 K. Ionization-induced processes and local nonstoichiometry induced by oxygen migration and desorption are possible mechanisms for the electron-beam- induced recrystallization and for the formation of the structural contrast features, respectively.

scholarly journals Temperature Calibration forIn SituEnvironmental Transmission Electron Microscopy Experiments

2015 ◽  
Vol 21 (6) ◽  
pp. 1622-1628 ◽  
Author(s):  
Jonathan P. Winterstein ◽  
Pin Ann Lin ◽  
Renu Sharma
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Elevated Temperatures ◽  
Lattice Parameter ◽  
Hydrogen Gas ◽  
Material Behavior ◽  
Sample Temperature ◽  
Transmission Electron ◽  
Local Sample

AbstractIn situenvironmental transmission electron microscopy (ETEM) experiments require specimen heating holders to study material behavior in gaseous environments at elevated temperatures. In order to extract meaningful kinetic parameters, such as activation energies, it is essential to have a direct and accurate measurement of local sample temperature. This is particularly important if the sample temperature might fluctuate, for example when room temperature gases are introduced to the sample area. Using selected-area diffraction (SAD) in an ETEM, the lattice parameter of Ag nanoparticles was measured as a function of the temperature and pressure of hydrogen gas to provide a calibration of the local sample temperature. SAD permits measurement of temperature to an accuracy of ±30°C using Ag lattice expansion. Gas introduction can cause sample cooling of several hundred degrees celsius for gas pressures achievable in the ETEM.

scholarly journals In-situ Transmission Electron Microscopy at pressures above 1 bar and elevated temperatures

2012 ◽  
Vol 18 (S2) ◽  
pp. 1114-1115 ◽  
Author(s):  
H. Zandbergen
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Elevated Temperatures ◽  
Transmission Electron

Extended abstract of a paper presented at Microscopy and Microanalysis 2012 in Phoenix, Arizona, USA, July 29 – August 2, 2012.

In-Situ High Resolution Transmission Electron Microscopy of Dynamic Events During the Amorphous to Crystalline Phase Transformation in Silicon

1985 ◽  
Vol 62 ◽  
Author(s):  
M. A. Parker ◽  
T. W. Sigmon ◽  
R. Sinclair
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Phase Transformation ◽  
Solid State ◽  
High Resolution ◽  
Elevated Temperatures ◽  
Video Recording ◽  
Dynamic Events ◽  
Transmission Electron

ABSTRACTA technique has been developed which employs high resolution transmission electron microscopy (HRTEM) for the observation of the atomic mechanisms associated with solid state phase transformation as they occur at elevated temperatures. It consists of the annealing in-situ of cross-section transmission electron microscopy (TEM) specimens that have been favorably oriented for lattice fringe imaging and the video-recording of dynamic events as they occur in real-time. By means of this technique, we report the first video-recorded lattice images of crystallographic defect motion in silicon, viz. the motion of dislocations and stacking faults, as well as the first such images of the atomic mechanisms responsible for the amorphous to crystalline (a-c) phase transformation, viz. heterogeneous nucleation of crystal nuclei, coalescence of crystal nuclei by co-operative atomic processes, ledge motion at the growth interface, and normal growth in silicon. This technique holds great potential for the elucidation of the atomic mechanisms involved in reaction kinetics in the solid state.

scholarly journals Visualizing Ligand-Mediated Bimetallic Nanocrystal Formation Pathways with In Situ Liquid Phase Transmission Electron Microscopy Synthesis

2020 ◽  
Author(s):  
Mei Wang ◽  
Asher Leff ◽  
Yue Li ◽  
Taylor Woehl
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Beam ◽  
Ex Situ ◽  
Formation Mechanisms ◽  
Transmission Electron ◽  
Thiolate Complexes ◽  
Nanocrystal Formation ◽  
Phase Transmission

Colloidal synthesis of alloyed multimetallic nanocrystals with precise composition control remains a challenge and a critical missing link in theory-driven rational design of functional nanomaterials. Liquid phase transmission electron microscopy (LP-TEM) enables directly visualizing nanocrystal formation mechanisms that can inform discovery of design rules for colloidal multimetallic nanocrystal synthesis, but it remains unclear whether the salient chemistry of the flask synthesis is preserved in the extreme electron beam radiation environment during LPTEM. Here we demonstrate controlled in situ LP-TEM synthesis of alloyed AuCu nanoparticles while maintaining the molecular structure of electron beam sensitive metal thiolate precursor complexes. Ex situ flask synthesis experiments showed that nearly equimolar AuCu alloys formed from heteronuclear metal thiolate complexes, while gold-rich alloys formed in their absence. Systematic dose rate-controlled in situ LP-TEM synthesis experiments established a range of electron beam synthesis conditions that formed alloyed AuCu nanoparticles with similar alloy composition, random alloy structure, and particle size distribution shape as those from ex situ flask synthesis, indicating metal thiolate complexes were preserved under these conditions. Reaction kinetic simulations of radical-ligand reactions revealed that polymer capping ligands acted as effective hydroxyl radical scavengers during LP-TEM synthesis and prevented metal thiolate oxidation at low dose rates. In situ synthesis experiments and ex situ atomic scale imaging revealed that a key role of metal thiolate complexes was to prevent copper atom oxidation and facilitate formation of prenucleation cluster intermediates. This work demonstrates that complex ion precursor chemistry can be maintained during LP-TEM imaging, enabling probing nanocrystal formation mechanisms with LP-TEM under reaction conditions representative of ex situ flask synthesis.

Direct Observation of Defect Motion in Silicon By High-Resolution Transmission Electron Microscopy

1985 ◽  
Vol 43 ◽  
pp. 358-359
Author(s):  
M. A. Parker ◽  
R. Sinclair
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Beam ◽  
High Resolution ◽  
Crystal Defects ◽  
Incident Electron Beam ◽  
Transmission Electron ◽  
Heating Effects ◽  
Electron Beam Heating

Observations of defect motion by high resolution transmission electron microscopy (HRTEM) are rare. Unfortunately, the application of this technique has been limited to a few unique materials, those that can obtain sufficient thermal energy for the initiation of atomic motion through the heating effects of the incident electron beam. In earlier work, it was speculated that events such as the motion of crystal defects, observed in cadmium telluride (CdTe) with the electron beam heating method, might become evident in materials such as silicon (Si) if only sufficiently high temperatures could be achieved (∼ 600°C) in-situ.A silicon specimen with a suitable population of defects was chosen for examination; it consisted of a cross-section of.3 μ ﹛100﹜ silicon on ﹛1102﹜ sapphire (SOS from Union Carbide) which was implant amorphized by 28Si+ ion implantation at an energy of ∼ 170keV.

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