ANALYSIS OF EXTENDED DEFECTS IN MELT-GROWN GASE SINGLE-CRYSTALS BY CONVERGENT-BEAM ELECTRON-DIFFRACTION TECHNIQUES

Stacking faults and dislocations in melt-grown GaSe single crystals have been studied by convergent-beam electron diffraction techniques. The modifications induced by stacking faults in some reflections of the large-angle convergent-beam electron diffraction patterns and the splitting induced by dislocations in some reflections of the low-camera-length diffraction patterns have been used in order to determine the displacement vector of stacking faults and Burgers vector of dislocations. In addition, distortions induced by isolated dislocations in large-angle convergent-beam electron diffraction patterns have been used to discriminate quickly edge and partial dislocations.