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 Si(3)N(4) 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 < or =0.1eV 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 degrees filter) of the SESAM2. A procedure is proposed for the correction of the non-isochromaticity.