New 300 kV energy-filtering field emission electron microscope

In order to observe high-spatial-resolution elemental images using inelasti c electrons, a 300 kV energy-filtering transmission electron microscope wit h an omega-type energy filter has been developed. Some characteristic featu res of the new microscope are described. The accelerating voltage dependenc e of the inelastic images is calculated to confirm that the spatial resolut ion for the elemental images is improved with an increase in the voltage fr om 120 kV to 300 kV. It is shown that a single atomic layer of oxygen atoms in AI(11)O(3)N(9) crystal is well imaged as a bright line with a periodic separation of 2.9 nm along the c-axis. The spatial resolution for the oxyge n images is about 0.5 nm, which corresponds well with the theoretical calcu lation.