Measurement of surface defects by low-energy electron diffraction

Low-energy electron diffraction is capable of detection of non-periodic arrangements by spot profile analysis (SPA-LEED). All kinds of defects may be identified by a qualitative and nevertheless systematic evaluation of the diffraction pattern with respect to spot shape, background and energy dependance. It is shown that the kinematical approximation provides far reaching results. The importance and achievements of the newly developed high-resolution instrumentation is demonstrated. The quantitative evaluation provides data on defect density and distribution, which are not available otherwise, as demonstrated with examples. A comparison of imaging and diffraction techniques shows the special advandages of diffraction with respect to quantitative analysis.