Structural and Phase Transformations in Thin Film Ti-Aluminides and Ti/Al Multilayers

1996 ◽  
Vol 434 ◽  
Author(s):  
R. Banerjee ◽  
S. Swaminathan ◽  
R. Wheeler ◽  
H. L. Fraser
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Layer Thickness ◽  
High Resolution Electron Microscopy ◽  
Silicon Substrates ◽  
Two Phase ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Sputter Deposited

AbstractMultilayered Ti/Al thin films (with nominally equal layer thickness of Ti and Al) have been sputter deposited on oxidized silicon substrates at room temperature. Transmission electron microscopy (TEM) and high resolution electron microscopy have been used to characterize the structure of these multilayers as a function of the layer thickness. Ti changed from an hcp to an fcc and back to an hcp structure on reduction of the layer thickness. Al too changed from an fcc to an hcp structure at a layer thickness of 2.5 nm. The observed structural transitions have been explained on the basis of the Redfield-Zangwill model. Subsequently Ti-aluminide thin films were deposited using a γ-TiAl target. These films were found to be amorphous in the as-deposited condition with crystallites of α-Ti(Al) embedded in the amorphous matrix. On annealing under a protective Ar atmosphere at a temperature of 550 °C, the Ti-aluminide film crystallized into a nanocrystalline two phase microstructure consisting of γ-TiAl and α2-Ti3Al. The crystallization of the aluminide film has been investigated in detail by in-situ annealing experiments on a hot stage in the TEM. The results of this investigation have been discussed in this paper.

scholarly journals Quantitative In-Situ Nanoindentation of Thin Films in a Transmission Electron Microscope

2001 ◽  
Vol 7 (S2) ◽  
pp. 912-913
Author(s):  
A.M. Minorl ◽  
E.A. Stach ◽  
J.W. Morris
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Real Time ◽  
Silicon Substrates ◽  
Boron Doped Diamond ◽  
Boron Doped ◽  
Transmission Electron ◽  
Diamond Indenter ◽  
Force Calibration

A unique in situ nanoindentation stage has been built and developed at the National Center for Electron Microscopy in Berkeley, CA. By using piezoceramic actuators to finely position a 3-sided, boron-doped diamond indenter, we are able to image in real time the nanoindentation induced deformation of thin films. Recent work has included the force-calibration of the indenter, using silicon cantilevers to establish a relationship between the voltage applied to the piezoactuators, the displacement of the diamond tip, and the force generated.In this work, we present real time, in situ TEM observations of the plastic deformation of Al thin films grown on top of lithographically-prepared silicon substrates. The in situ nanoindentations require a unique sample geometry (see Figure 1) in which the indenter approaches the specimen normal to the electron beam. in order to meet this requirement, special wedge-shaped silicon samples were designed and microfabricated so that the tip of the wedge is sharp enough to be electron transparent.

Studies of Material Reactions by In Situ High-Resolution Electron Microscopy

MRS Bulletin ◽  
1994 ◽  
Vol 19 (6) ◽  
pp. 26-31 ◽  
Author(s):  
Robert Sinclair
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Atomic Scale ◽  
Ex Situ ◽  
New Materials ◽  
Kinetic Measurements ◽  
Transmission Electron ◽  
Resolution Electron

Processing has always been a key component in the development of new materials. Basic scientific understanding of the reactions and transformations that occur has obvious importance in guiding progress. Invaluable insight can be provided by observing the changes during processing, especially at high magnification by in situ microscopy. Now that this can be achieved at the atomic level by using high-resolution electron microscopy (HREM), atomic behavior can be seen directly. Accordingly, many deductions concerning reactions in materials at the atomic scale are possible.The purpose of this article is to illustrate the level reached by in situ HREM. The essential procedure is to form a high-resolution image of a standard transmission electron microscope (TEM) sample and then to alter the structure by some means in a controlled manner, such as by heating. Continual recording on videotape allows subsequent detailed analysis of the behavior, even on a frame-by-frame (1/30 second) basis. The most obvious advantage is to follow the atomic rearrangements directly in real time. However, in addition, by continuous recording no stages in a reaction are missed, which can often occur in a series of conventional ex situ annealed samples because of the limited number of samples that can realistically be examined by HREM. One can be sure that the same reaction, in the same area, is being studied. Furthermore, by changing the temperature systematically, extremely precise kinetic measurements can be made (e.g., for activation energies and kinetic laws) and the whole extent of a material transformation can be investigated in one sample, something that would take months of work if studied conventionally. The information provided by in situ HREM is often unique and so it can become an important technique for fundamental materials investigations.

Bio-camouflage of anatase nanoparticles explored by in situ high-resolution electron microscopy

Nanoscale ◽  
2017 ◽  
Vol 9 (30) ◽  
pp. 10684-10693 ◽  
Author(s):  
Ana R. Ribeiro ◽  
Arijita Mukherjee ◽  
Xuan Hu ◽  
Shayan Shafien ◽  
Reza Ghodsi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Titanium Dioxide ◽  
Titanium Dioxide Nanoparticles ◽  
High Resolution Electron Microscopy ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Liquid Cell ◽  
Anatase Nanoparticles

In situliquid cell transmission electron microscopy and graphene liquid cells were used to investigate, thein situnano–bio interactions between titanium dioxide nanoparticles and biological medium.

New Insights on the Morphology of Nanocomposite Prepared by In Situ Emulsion Polymerization

2015 ◽  
Vol 775 ◽  
pp. 170-175
Author(s):  
José Costa de Macêdo Neto ◽  
João Evangelista Neto ◽  
Nayra Reis do Nascimento ◽  
Sheila Contant ◽  
Liliane Maria Ferrareso Lona
Keyword(s):  
Electron Microscopy ◽  
High Resolution Electron Microscopy ◽  
X Ray Diffraction ◽  
Nanocomposite Powder ◽  
Thin Sections ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Level Of Details ◽  
High Level

In order to better understand the morphology and properties of polymer nanocomposites it is necessary to conduct their characterization by Transmission Electron Microscopy (TEM). This work shows a technique through which the nanocomposite powder is mixed with a resin, and after cured, thin sections can be obtained by ultramicrotomy. Another technique presented in this work deals with the observation of clay powder in solution. In this work High Resolution Electron Microscopy (HRTEM) was used to obtain images of the nanocomposites and clay. Images with a high level of details were showed. Through the use of such techniques, it was possible to observe two types of clay morphology in polymer matrix and its distribution. The dimensions and hexagonal layers of the natural clay used as nanofiller for the nanocomposite were also observed. The X-ray Diffraction (XRD) was used to investigate the kaolinite and nanocomposite.

High Resolution Transmission Electron Microscopy of Some Catalysts

1986 ◽  
Vol 41 (3) ◽  
pp. 478-482 ◽  
Author(s):  
G. W. Qiao ◽  
J. Zhou ◽  
K. H. Kuo
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Iron Catalyst ◽  
Supported Catalyst ◽  
Rare Earth Oxide ◽  
High Resolution Electron Microscopy ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Damage Processes

Application of high resolution electron microscopy (HREM) to the study of Pt-Sn/γ-Al2O3 supported catalyst, zeolites, iron catalyst for ammonia synthesis, rare-earth oxide catalysts, etc., is described. Micro-twins, dislocations and other crystallographic imperfections are observed. Moreover, the structure images of channels representing columns of cages in several kinds of zeolites as well as radiation damage processes in them have been recorded in situ. The observed images of zeolites were found to be in good agreement with the structure model projections and computer simulated images.

Direct Correlation of Transport Properties and Microstructure In Y1Ba2Cu3O7-x Thin Film Grain Boundaries

1994 ◽  
Vol 357 ◽  
Author(s):  
B. V. Vuchic ◽  
K. L. Merkle ◽  
D. B. Buchholz ◽  
R. P. H. Chang ◽  
L. D. Marks
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Grain Boundaries ◽  
High Resolution Electron Microscopy ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Current Voltage ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis ◽  
The Individual

AbstractIndividual 45° [001] tilt grain boundaries in Y1Ba2Cu3O7-x thin films grown on biepitaxial substrates were studied. The thin films were grown using both pulsed organometallic beam epitaxy (POMBE) and laser ablation. Transport characteristics of the individual grain boundaries were measured including resistance - temperature (R-T) and current - voltage (I-V) dependencies with and without an applied magnetic field. In order to elucidate possible structural origins of the differences in transport behavior, the same grain boundaries which were electrically characterized were subsequently thinned for electron-microscopy analysis. Transmission-electron-microscopy and high-resolution-electron-microscopy were used to structurally characterize the grain boundaries. The macroscopic and microscopic structures of two boundaries, a nominally resistive and a superconducting grain boundary, are compared.

Strain measurements in s-Si/SiGe nanostructures by quantitative high-resolution electron microscopy

2007 ◽  
Vol 1026 ◽  
Author(s):  
Florian Hüe ◽  
Martin Hÿtch ◽  
Hugo Bender ◽  
Jean-Michel Hartmann ◽  
Alain Claverie
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Layer Thickness ◽  
High Resolution Electron Microscopy ◽  
Strained Si ◽  
Nanoelectronic Devices ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Channel Region ◽  
Aberration Corrected

AbstractWe have studied strained Si layers grown on Si1-xGex virtual substrate (VS) by high-resolution transmission electron microscopy (HRTEM). Aberration-corrected HRTEM coupled with geometric phase analysis (GPA) provides precise measurements of strain. Different parameters are investigated: the VS composition (x=20, 30, 40 and 50%) and the s-Si layer thickness. Finite element method simulations confirm our measurements. Measurements and simulations lead to the conclusion that the strain state of the deposited layer is independent of the layer thickness. We apply the technique to measuring strains in the channel region of a p-MOSFET and show that the technique is a promising metrological tool for nanoelectronic devices.

Interface structures in polycrystalline ceramic materials

1986 ◽  
Vol 44 ◽  
pp. 468-471
Author(s):  
K. J. Morrissey
Keyword(s):  
Electron Microscopy ◽  
Analytical Electron Microscopy ◽  
Physical And Mechanical Properties ◽  
High Resolution Electron Microscopy ◽  
Ceramic Materials ◽  
Polycrystalline Materials ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Interface Structures

Grain boundaries and interfaces play an important role in determining both physical and mechanical properties of polycrystalline materials. To understand how the structure of interfaces can be controlled to optimize properties, it is necessary to understand and be able to predict their crystal chemistry. Transmission electron microscopy (TEM), analytical electron microscopy (AEM,), and high resolution electron microscopy (HREM) are essential tools for the characterization of the different types of interfaces which exist in ceramic systems. The purpose of this paper is to illustrate some specific areas in which understanding interface structure is important. Interfaces in sintered bodies, materials produced through phase transformation and electronic packaging are discussed.

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