Image conservation in inelastically scattered electrons in reflection electron microscopy

Energy-filtered reflection electron microscope (REM) images of well-defined surfaces were taken for the first time using an ultrahigh vacuum electron microscope equipped with an omega filter. Si(1 1 1)7 x 7 and Si(1 1 1)5 x 2-Au surfaces were imaged. Images using electrons with energy losses of 11.3 and 22.6 eV (single and double surface plasmon excitation) showed lattice fringes of Si(1 1 1)7 x 7(2.3 nm in spacing) and Si(1 1 1)5 x 2-Au(1.7 nm). The observation gave the first experimental evidence that diffraction image contrast is conserved in images formed by electrons inelastically scattered by small angles in REM; as in the case of transmission electron microscopy.