In situ Electron Microscopy and its applications to semiconductor reactions at high-resolution

Author(s):  
Robert Sinclair

In situ electron microscopy experiments can provide the most revealing insights into material behavior. However, in order to take full advantage of the observations, quantitative measurements are required so that the underlying mechanisms are completely interpreted. This approach also ensures that specimen and environmental artifacts do not play a role and that real “bulk” processes are being studied. These points are illustrated in this paper by reference to work on reactions in semiconductor systems, especially at high resolution.The technique and practice of in situ microscopy are quite exacting. Thus it is often necessary to record changes in the same specimen area for extensive periods of time (e.g., hours), under identical imaging conditions. One can never be sure when a significant event will take place, or sometimes whether it has actually occurred -- accordingly a high degree of acuity on behalf of the observer is essential. A number of procedures is recommended to check that the results are representative and reproducible, including comparing the structural evolution with that from ex situ samples both qualitatively and quantitatively (e.g., [1]). Some contemporary applications are given in a recent publication.

Author(s):  
Zhi-Peng Wu ◽  
Hui Zhang ◽  
Cailing Chen ◽  
Guanxing Li ◽  
Yu Han

Oxygen electrocatalysis involving the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) plays a vital role in cutting-edge energy conversion and storage technologies. In situ studies of the evolution of catalysts during oxygen electrocatalysis can provide important insights into their structure - activity relationships and stabilities under working conditions. Among the various in situ characterization tools available, in situ electron microscopy has the unique ability to perform structural and compositional analyzes with high spatial resolution. In this review, we present the latest developments in in situ and quasi-in situ electron microscopic techniques, including identical location electron microscopy, in situ liquid cell (scanning) transmission electron microscopy and in situ environmental transmission electron microscopy, and elaborate their applications in the ORR and OER. Our discussion centers on the degradation mechanism, structural evolution and structure - performance correlations of electrocatalysts. Finally, we summarize the earlier discussions and share our perspectives on the current challenges and future research directions of using in situ electron microscopy to explore oxygen electrocatalysis and related processes.


MRS Bulletin ◽  
1994 ◽  
Vol 19 (6) ◽  
pp. 26-31 ◽  
Author(s):  
Robert Sinclair

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.


2013 ◽  
Vol 19 (S2) ◽  
pp. 404-405
Author(s):  
C. Mueller ◽  
M. Harb ◽  
J.R. Dwyer ◽  
R.J.D. Miller

Extended abstract of a paper presented at Microscopy and Microanalysis 2013 in Indianapolis, Indiana, USA, August 4 – August 8, 2013.


2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Shuyi Zhang ◽  
Chen Chen ◽  
Matteo Cargnello ◽  
Paolo Fornasiero ◽  
Raymond J. Gorte ◽  
...  

2003 ◽  
Vol 17 (15) ◽  
pp. 791-801 ◽  
Author(s):  
V. V. Volkov ◽  
M. A. Schofield ◽  
Y. Zhu

We report our study on magnetic structural evolution of artificially patterned micron and submicron magnetic arrays as a function of applied field using in situ electron microscopy. To understand magnetic dynamics and switching behavior we employ our newly developed phase retrieval method, based on Lorentz phase microscopy, to map local induction distribution at nanometric scale. We outline the principle of the new method and discuss its advantages and drawbacks in comparison with off-axis electron holography.


2018 ◽  
Vol 24 (S1) ◽  
pp. 10-11
Author(s):  
Robert Sinclair ◽  
Yunzhi Liu ◽  
Sangchul Lee ◽  
Ai Leen Koh

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