Abstract: | Reconstructed structures at monolayer level on ‘clean and well-defined’ surfaces can be imaged by transmission electron microscopy in fixed beam illumination mode. The specimens are cleaned in-situ in the electron microscope in ultra high vacuum. Transmission electron diffraction pattern intensities can give useful information for determining the surface unit cell size of the structure, and the atom positions (geometric arrangement of atoms in the unit cell) especially those with a large unit cell, since the diffraction intensities are interpreted kinematically. High resolution surface imaging which gives directly the atom positions is tested here for a single monolayer terrace on Ag (111) surface. The result shows the value of HREM for studies of surface crystallography. |