Energy-selected electron diffraction experiments using the rocking-crystal method in the raster microscope for the investigation of localization effects in single crystals

The effect of the localization of Bloch waves, i.e., the nonhomogeneous electron current density distribution over the crystal unit cell, was investigated. The electron diffraction patterns were taken with the rocking-crystal method using a microprocessor-controlled raster electron microscope. A program for computer aided indexing and orientation determination is demonstrated. Energy-selected electron diffraction patterns were obtained using a magnetic sector-field spectrometer, integrated in the process controls and a two-energy detection system allowing background-corrected characteristic energy loss patterns. The localization effect of Bloch waves in graphite and silicon was investigated using characteristic energy loss diagrams. In graphite, the localization contrast was emphasized by a special detector position. The possibilities of impurity position determination in single crystals using the localization contrast are demonstrated.