Transmission electron microscopy for the characterization of nanoscale materials

Understanding the physical and chemical properties of various materials demands detailed knowledge about their shape, structure, and composition. Particularly for nanoscale materials, characterization methods with high spatial and analytical resolution are required. Due to the small wavelength of strongly accelerated electrons, transmission electron microscopy (TEM) is one of the most appropriate nanoscale analysis techniques. Moreover, due to the tremendous range of signals arising from electron-solid interaction, a broad range of analysis modes are nowadays available in a transmission electron microscope.
After introducing the advantages of TEM, the basic setup of a transmission electron microscope, and the equipment available at HZDR for performing TEM analyses, the most important modes of imaging are presented, including bright-field, dark-field, and high-resolution imaging in TEM and scanning TEM (STEM) mode. It is shown, how diffraction analysis is used to derive structure and orientation information, while energy-dispersive X-ray spectroscopy (EDXS) and electron energy-loss spectroscopy (EELS) are applied for chemical composition analysis. Using examples from various research and application fields, including e.g. information technology, resource ecology, and radiopharmacy, the various TEM analysis modes are illustrated, and their combination is shown to be essential for a comprehensive understanding of nanoscale materials.