Nanoscale analysis by energy-filtering TEM

Abstract

This chapter discusses the nanoscale analysis by energy-filtering TEM. In transmission electron microscopy (TEM), inner-shell excitation of the atoms by the beam electrons leads to characteristic edges in the electron energy-loss (EEL) spectrum. The onset energies of each edge can be used to identify the presence of individual chemical elements. The concentration of an element can be determined from an EEL spectrum if the pre-edge background is extrapolated and subtracted from the signal obtained above the edge. With the use of an energy-filtering TEM, the information about the distribution of electrons that suffered a specific energy loss can be gathered in a two-dimensional way, a technique that is referred as “electron spectroscopic imaging” (ESI). The chapter discusses new ESI-based techniques, which are used for elemental mapping, quantitative analysis, and spatially resolved analysis of the energy-loss near-edge fine structure (ELNES). The detection and resolution limits are discussed and an outlook on future trends in energy filtering TEM is also provided in the chapter.