Electron Beam Diffraction and Microscopy of Atomic‐Scale Geometrical Structure

Electron beams enable multiple important probes of geometrical structure at electronic material surfaces and interfaces. These structural probes are based on electron diffraction, secondary electron imaging, transmission electron atomic imaging and atom-specific electron energy loss. Low energy electron diffraction (LEED) has provided the majority of surface structural data, which is supplemented by scanning tunneling microscopy (STM) and other techniques. Reflection high energy electron diffraction (RHEED) uses a grazing incidence electron beam at much higher energies than LEED, to monitor surface order during epitaxial growth. The scanning electron microscopy (SEM) provides electron excitation for a number of spectroscopies such as AES, XPS, energy dispersive X-ray analysis (EDAX), and cathode luminescence spectroscopy (CLS). Transmission electron microscopy (TEM) provides one of the most direct methods of imaging interfaces. LEED and RHEED have provided a wealth of information on surface atomic reconstructions, which depend on surface orientation, growth temperature, surface stoichiometry, and thermal annealing.