Electron Microscopy SEM and TEM

One problem with methods that produce polycrystalline or nanocrystalline material is that it is not feasible to characterize electrically dopants in such materials by the traditional four-point-probe contacts needed for Hall measurements. Other characterization methods such as optical absorption, photoluminescence (PL), Raman, X-ray and electron diffraction, X-ray rocking-curve widths to assess crystalline quality, secondary ion mass spectrometry (SIMS), scanning or transmission electron microscopy (SEM and TEM), cathodolumi-nescence (CL), and wet-chemical etching provide valuable information, but do not directly yield carrier concentrations. 

The solid surfaces and interfaces are investigated using surface profiler or imaging equipments such as scanning tunneling microscopy (STM), atomic force microscopy (AFM), scanning electron microscopy (SEM) and TEM in order to quantity the... 

Scanning and transmission electron microscopies (SEM and TEM, respectively) were realized at IFF. SEM micrographs were obtained on a JEOL 6340 F and TEM micrographs on a JEOL 100 CX or a JEOL 120 CX. 

Diffuse reflectance UV-Vis spectroscopy (DREAS) and EPR provide useful information regarding the oxidation state of the metal. Other techniques that are regularly applied are MAS-NMR, X-ray photoelectron spectroscopy (XPS) and scanning and transmission electron microscopy (SEM and TEM). Finally, BET surface area measurements and adsorption experiments are indispensible for checking the stractural integrity of the molecular sieve. 

The microstructures of the consolidated and deformed samples were characterized by X-ray diffraction, optical and electron microscopy (SEM and TEM). The samples for mechanical testing have been prepared by spark erosion. The linear thermal expansion was determined by using a thermomechanical system (TMA). The temperature-dependent elastic moduli have been measured by the resonance frequency and the pulse-echo method. The bulk moduli were determined by synchrotron radiation diffraction using a high-pressure diamond-die cell at HASYLAB. The compression and creep tests were performed with computer-controlled tensile testing and creep machines. 

Electron microscopy SEM and TEM provide a way to directly observe nanoparticles, physical characterization of nanoparticles... 

All the samples were characterized by thermogravimctiy (TG/DTG/DTA), nitrogen physical adsorption. X-ray powder diffraction (XRD) and electron microscopy (SEM and TEM). The thermal analyses were all performed by raising the temperature linearly at 20K min in air and a STA-780. 

In situ observation of the polymerization process of /3-CF by polarization optical microscopy (POM), scanning electron microscopy (SEM), and TEM provided information on the molecular orientation within the spherulites of synthetic cellulose [43]. POM observations revealed that two types of spherulites were formed one displaying a well-defined Maltese cross identified... 

FTIR, NMR, and EXAFS and ex situ methodologies such as electron microscopy (SEM and TEM) are also powerful and important tools in the investigation of the mechanisms by which materials form. Combination of experimental approaches not only facilitates their interpretation but also enables cross-correlation between experimental phenomena. This is especially important because SAXS provides information on reciprocal space. The estimation of the structure of a scatterer from its scattering profiles is called the inverse scattering problem, and this problem cannot be solved uniquely [1]. Scattering profiles are complicated further when polydispersity effects are operative, which is usually to some extent the case for sol-gel systems. In practice, the interpretation of SAXS patterns therefore depends heavily on the development of hypothetical structural models and on comparison of the simulated scattering profile, which can be calculated from a given structure, with the experimental profile. Hence, additional independent structural or chemical information may aid in the interpretation of SAXS profiles. 

Scanning Electron Microscopy The major difference between scanning electron microscopy (SEM) and TEM is that in the former, electron beams are scanned over a region of the sample surface. When electron beams interact with the sample in a depth of a few to hundreds of nanometers, a variety of backward detectable signals can be collected, including secondary electrons, backscattered electrons. X-rays, and so on. [40, 41 ]. Each of them can be used to characterize the sample with respect to different properties. The backscattered electrons result from the collision of incident electrons... 

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