Topic1: New Trends in Electron Microscopy
The lecture presents the newest developments in electron microscope and the new research tendencies in electron microscopy. Electron microscopy is one of most important tools used for characterization in materials science. The new trends in electron microscopy are based on the recent developments in electron optics. The corrections of imaging lens aberration and probe lens aberration improve the spatial resolution of TEM and STEM down to sub-nanometer region. This allows the imaging of light element atoms in periodic system and the imaging of heavy atoms in bulk and on the surface of materials. Quantitative structure analysis of grain boundary/interface at atomistic scale becomes available. The development of monochromator reduces the energy broadness of emitted electron beam significantly so that electron energy-loss spectrum (EELS) with an energy-resolution comparable to that of X-ray adsorptions spectrum (XAS) can be obtained to study the electronic structure at nano-scale. The new trends in electron microscopy is presented using examples of imaging the light elements in oxide complex and in the planer/linear defects; imaging the atomistic structure of interface/grain boundary; imaging small clusters and point defects/doping atom; quantitative chemical analysis of atomic column/doping atoms and electron tomography.
Topic2: Transmission electron microscopy and nanoscience
The lecture gives an overview how transmission electron microscopy (TEM) opens the horizon of nanoscience, nanotechnology and nanomaterials and accelerates their developments. The talk starts with the history of observation or discovery of carbon nanotubes, one of the key materials in nanotechnology and nanoscience. TEM with its high spatial resolution, combined with analytical methods such as energy-dispersive X-ray spectroscopy (EDS) and electron energy-loss spectroscopy (EELS), has become an indispensable tool in characterization of nanoparticles and nanomaterials. The geometric, morphologic, electronic and chemical information can be in principle simultaneously or subsequently determined from the studied sample by means of this unique method. It is but also demonstrated that TEM is more than a simple imaging/diffraction technique. TEM has been successfully used to study in-situ the growth mechanism of carbon nanotubes and nanofibers on supports catalyzed by metal particles. In nanocatalysis, TEM is widely used to study the redox dynamic of metal nanoparticles in chemical reaction. The application of TEM in study the microstructure and mechanical property of metal oxide nanostructure will be discussed.
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