Published online by Cambridge University Press: 26 February 2011
The electron microscope can be operated in several different modes to provide atomic-level detail about surfaces. The REM technique with glancing-angle incidence permits the topography of bulk surfaces to be characterized with a resolution of better than 10A, and atomic-step-height features are visible. The standard TEM bright- and dark-field modes can also be used with appropriate samples to provide monolayer sensitivity. The profile imaging technique is ideal for following real-time dynamic processes. Typical vacuum levels ( ∼10−7 torr), and the lack of facilities for surface cleaning, currently impose a restriction on the materials which can be usefully studied in most available microscopes. Clean and well-defined environments for the sample, without any compromise of the microscope performance, will become increasingly common in the near future.