ENERGY-FILTERED CONVERGENT-BEAM DIFFRACTION - EXAMPLES AND FUTURE-PROSPECTS

The addition of an imaging filter to a cold field-emission TEM has led to the development of new techniques based on the analysis of the zer o-loss or a specific energy-loss signal. For example, the removal of i nelastically scattered electrons can improve the fringe contrast in co herent CBED patterns from relatively thick crystals. Similarly, this e nergy-filtering is essential for the accurate measurement of low-order structure factors by CBED pattern matching. Studies of convergent-bea m patterns recorded at specific core-loss energies show that they cont ain chemically sensitive features. In addition, hybrid modes of operat ion have been developed that allow spectrum-images and spectrum-diffra ction patterns to be obtained. New results are presented that show the use of these techniques. Finally, it is argued that energy-filtering should lead to improvements in critical-voltage measurements, lattice- parameter determination and in the resolution of branch cluster inform ation.