Electron Energy-Loss Spectroscopy and Energy-Filtered Electron Imaging

Electron energy-loss spectroscopy (EELS) is one of the most important analytical tools that modern transmission electron microscopy (TEM) possesses. EELS is powerful not only in quantitative chemical microanalysis but also in probing local chemical-bonding information. Using a ultrafine electron probe, EELS analysis can be carried out from a region smaller than 1 nm. The analytical information from EELS can be combined with the image and diffraction data provided by TEM, providing a comprehensive characterization on the local atomic, chemical, and electronic structures (1–3). As an extensive development of EELS, energy-filtered electron imaging has been implemented in recent years, which allows high-spatial-resolution chemical imaging as well as imaging using fine structures provided by EELS (4). The most recent advances in developing a fine electron probe, as small as 0.1–0.2 nm, allows chemical analysis atomic column-by-column (5,6). These powerful techniques are undoubtedly the most effective tools that can be used in complementary with high-resolution TEM for quantitative structure determination of materials that are of importance to industry applications. The objective of this chapter is to outline the fundamentals of EELS, energy-filtered electron imaging, and their applications in analysis of chemical and electronic structures of inorganic materials. This chapter serves as an introduction to these techniques and our emphasis is on their applications in problems of interesting to industry.