Use of the curvature method to determine the misfit stress of epitaxial semiconducting systems: the case of samples thinned for TEM observation.

2003 ◽  
Vol 795 ◽  
Author(s):  
A. Ponchet ◽  
M. Cabié ◽  
L. Durand ◽  
M. Rivoal ◽  
A. Rocher

ABSTRACTThe curvature method which allows to measure the stress in epitaxial layers has been adapted to transmission electron microscopy observations. The samples thinned by the substrate side present some particular mechanical characteristics. The ratio between the substrate thickness and the layer thickness should be taken into account. The experimental conditions allowing a reliable determination of the stress have been established. A finite element calculation has been used to show that the dimensions of the area where the measure is performed can not systematically be neglected. This method has been applied to the semiconducting systems Ga1-xInxAs/GaAs and Ga1-xInxAs/InP.

Author(s):  
Marc J.C. de Jong ◽  
Wim M. Busing ◽  
Max T. Otten

Biological materials damage rapidly in the electron beam, limiting the amount of information that can be obtained in the transmission electron microscope. The discovery that observation at cryo temperatures strongly reduces beam damage (in addition to making it unnecessaiy to use chemical fixatives, dehydration agents and stains, which introduce artefacts) has given an important step forward to preserving the ‘live’ situation and makes it possible to study the relation between function, chemical composition and morphology.Among the many cryo-applications, the most challenging is perhaps the determination of the atomic structure. Henderson and co-workers were able to determine the structure of the purple membrane by electron crystallography, providing an understanding of the membrane's working as a proton pump. As far as understood at present, the main stumbling block in achieving high resolution appears to be a random movement of atoms or molecules in the specimen within a fraction of a second after exposure to the electron beam, which destroys the highest-resolution detail sought.


2009 ◽  
Vol 15 (S2) ◽  
pp. 134-135 ◽  
Author(s):  
C Phatak ◽  
E Humphrey ◽  
M DeGraef ◽  
A Petford-Long

Extended abstract of a paper presented at Microscopy and Microanalysis 2009 in Richmond, Virginia, USA, July 26 – July 30, 2009


2019 ◽  
Vol 97 (2) ◽  
pp. 140-146
Author(s):  
Tian Gan ◽  
Zhikai Wang ◽  
Mengru Chen ◽  
Wanqiu Fu ◽  
Haibo Wang ◽  
...  

In this work, the Ag@Cu particles with yolk–shell nanostructure was prepared by facile solvothermal method, which was modified on glassy carbon electrode (GCE) to fabricate electrochemical sensor for the convenient and fast determination of p-aminobenzoic acid (PABA). The surface morphology and electrochemical properties of the as-prepared Ag@Cu nanocomposite modified electrode were characterized by scanning electron microscopy, transmission electron microscopy, chronocoulometry, and electrochemical impedance spectroscopy. Further, the electrochemical sensing of PABA was performed on the Ag@Cu/GCE using cyclic voltammetry and differential pulse voltammetry techniques, showing high catalytic activity. Under the optimal conditions, the sensor exhibited a wide linear range, high sensitivity, and low detection limit of 0.315 μmol/L for PABA. The developed sensor was also successfully applied for PABA detection in anesthetic and cosmetics with satisfactory results.


2008 ◽  
Vol 112 (6) ◽  
pp. 1759-1763 ◽  
Author(s):  
Norihiko L. Okamoto ◽  
Bryan W. Reed ◽  
Shareghe Mehraeen ◽  
Apoorva Kulkarni ◽  
David Gene Morgan ◽  
...  

2009 ◽  
Vol 42 (3) ◽  
pp. 519-524 ◽  
Author(s):  
Song Li ◽  
Yudong Zhang ◽  
Claude Esling ◽  
Jacques Muller ◽  
Jean-Sébastien Lecomte ◽  
...  

A general calculation method is proposed to characterize the crystalline planes and directions of a faceted nanoparticle using transmission electron microscopy (TEM) imaging and diffraction modes. With the determination of the edge vectors and then the plane normal vectors in the screen coordinate system of TEM, their Miller indices in the crystal coordinate system can be calculated through coordinate transformation. The method is helpful for related studies of the determination of the surface structure of nanoparticles.


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