Cathodoluminescence studies of dislocation motion in IIb–VIb compounds deformed in SEM

Continuous observation of dislocation motion on the specimen surface of II_b–VI_b semiconducting compounds (CdS and CdTe) has been made using a scanning electron microscope (SEM) with the cathodoluminescence (CL) by use of a deformation apparatus installed in the SEM chamber. With the application of stress, SEM-CL patterns revealed an increasing density of dark spots that formed dark stripes along slip traces. For both CdS and CdTe crystals, regardless of the slip system involved, the dark spots corresponding to individual dislocations appeared in the SEM field without displaying their moving state and seldom disappeared, indicating that dislocations are immobilized after they travel a certain distance from the source with a high velocity. The investigation of slip-band growth in CdS showed that screw bands on the basal plane exhibit the photoplastic effect, whereas those on the prismatic plane do not, in accordance with the macroscopic deformation tests.