Electron reflection, diffraction and imaging of bulk crystal surfaces in TEM and STEM

Reflection electron microscopy (REM) is a new technique for real space imaging of bulk crystal surfaces. The REM is performed in a transmission electron microscope (TEM) or a scanning TEM (STEM) using high-energy electrons at a grazing incidence angle. A comprehensive review has been given on basic techniques, fundamental physics, studies of surface reconstructions, and special applications of REM. Theoretical calculations have been described to illustrate the resonance scattering processes of electrons at the bulk crystal surfaces in the geometry of reflection high-energy electron diffraction (RHEED). Fundamental contrast mechanisms of REM have been illustrated to show the surface sensitivity of REM. Applications of REM for in-situ imaging of surface dynamic processes have been summarized for studies of metals, semiconductors, metal-on-semiconductors, semiconductor-on-semiconductors, and ceramics. Inelastic excitations of crystal surfaces in RHEED have been examined to demonstrate a technique, reflection electron energy-loss spectroscopy (REELS), for studying surface electronic structures and determining surface chemical compositions. Finally, novel techniques used in conjunction with REM, such a secondary electron imaging, scanning tunnelling microscopy (STM) and electron holography, have been described to show the future development of REM.