Tunneling Electron Microscopy, TEM

Fig. 1 Sketches of break junction-type test beds for molecular transport. On the far left is a tunneling electron microscopy (TEM) image of the actual metallic structure in (mechanical) break junctions from the nanoelectronics group at University of Basel. The sketches in the middle (Reprinted by permission from Macmillan Publishers Ltd Nature Nanotechnology 4, 230-234 (2009), copyright 2009) and right (reproduced from Molecular Devices, A.M. Moore, D.L. Allara, and P.S. Weiss, in NNIN Nanotechnology Open Textbook (2007) with permission from the authors) show possible geometries for molecules between two gold electrodes, and (on the upper right) a molecule that has only one end attached across the junction...

Thermochemistry DSC (see Box 9.1) TGA (see Box 9.1) Vapour pressure measurements Solid-state NMR Ultramicroscopy Scanning electron microscopy (SEM) Tunnelling electron microscopy (TEM) Atomic force microscopy (AFM) Molecular dynamics... 

To identify the presence of nanoclusters in solutions that appear to be homogeneous, one typically uses light scattering and tunneling electron microscopy (TEM). Finke argues that TEM is the most definitive method to assess the presence or absence of nanoparticulate... 

Fig. 6 a Scanning electron microscopy (SEM) image of pyrolyzed H2TMPP matmals and b-d Tunneling electron microscopy (TEM) images of pyrolyzed CoTMPP mateaials. Adapted with permission from [124]. Copyright 2009 The Electrochemical Society... 

Experimentally, different structure- and surface-sensitive techniques such as in situ scanning tunnelling microscopy (STM), in situ X-ray diffraction (XRD), transition electron microscopy (TEM), and in situ infrared (IR) spectroscopy have been... 

In addition to surface analytical techniques, microscopy, such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), scanning tunneling microscopy (STM) and atomic force microscopy (AFM), also provide invaluable information regarding the surface morphology, physico-chemical interaction at the fiber-matrix interface region, surface depth profile and concentration of elements. It is beyond the scope of this book to present details of all these microscopic techniques. 

In 2008 Shin et al. used lETS and transmission electron microscopy (TEM) to characterize the chemical integrity and morphology of rubrene (C40H24) layers after deposition of an Fe top electrode [57]. The lETS spectra were consistent with the known IR- and Raman-active normal modes, which led the authors to conclude there were no chemical reactions with Fe. Cross-sectional TEM images showed continuous rubrene layers between the bottom Co layer and top Fe layer, with no evidence for small particle formation. Similar to the study by Santos et al., they found that the presence of an AI2O3 layer had a profound effect on the tunneling... 

Two-dimensional (2-D) crystallites are generally of a lower symmetry than 3-D crystals. The molecules in the 2-D crystallites cannot pack across a center of inversion as they most commonly do in 3-D. By applying modern analytical tools such as scanning tunneling and probe microscopy (STM, SPM), transmission electron microscopy (TEM), grazing incidence X-ray diffraction (GIXD), electrospray ionization (ESI) and matrix-assisted laser-... 

Since the porosity of carbons is responsible for their adsorption properties, the analysis of the different types of pores (size and shape), as well as the PSD, is very important to foresee the behavior of these porous solids in final applications. We can state that the complete characterization of the porous carbons is complex and needs a combination of techniques, due to the heterogeneity in the chemistry and structure of these materials. There exist several techniques for the analysis of the porous texture, from which we can underline the physical adsorption of gases, mercury porosimetry, small angle scattering (SAS) (either neutrons—SANS or x-rays—SAXS), transmission and scanning electron microscopy (TEM and SEM), scanning tunnel microscopy, immersion calorimetry, etc. 

The above historical remarks might convey a subtle and scattered impression. It is true that any direct evidence has not yet been presented in the sense that monocyclicity is proven by rotationally resolved spectroscopy, NMR spectroscopy, or high-resolution images by scanning tunneling microscopy (STM) or transmission electron microscopy (TEM). 

The basical theories, equipments, measurement practices, analysis procedures and many results obtained by gas adsorption have been reviewed in different publications. For macropores, mercury porosimetry has been frequently applied. Identification of intrinsic pores, the interlayer space between hexagonal carbon layers in the case of carbon materials, can be carried out by X-ray dififaction (XRD). Recently, direct observation of extrinsic pores on the surface of carbon materials has been reported using microscopy techniques coupled with image processing techniques, namely scarming tunneling microscopy (STM) and atomic force microscopy (AFM) and transmission electron microscopy (TEM) for micropores and mesopores, and scanning electron microscopy (SEM) and optical microscopy for macropores [1-3],... 

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