Plasmon energy mapping in energy-filtering transmission electron microscopy

In this paper, we demonstrate the two-dimensional mapping of plasmon energies by energy-filtering transmission electron microscopy. The maps are obtained from a series of energy-filtered images in the plasmon energy region. Examples are shown for a nano-crystalline Si–B–C–N ceramic. This material contains SiC and Si3N4 grains as well as intergranular regions composed of hexagonal BN (h-BN) and turbostratic carbon (t-C). The different phases can be clearly identified by their specific plasmon energies. An energy resolution of ⩽0.1 eV is achieved. In addition, the plasmon map of an amorphous carbon film is used to visualize the non-isochromaticity of the Corrected Omega filter (90° filter) of the SESAM2. A procedure is proposed for the correction of the non-isochromaticity.