In situ TEM observation of dislocation motion in II–VI compounds

Abstract

Dislocation motion in single crystals of the II-VI compounds (MS, (dSe, Zn() (wurtzite structure) and CdTe (zineblende structure) has been observed in silu by transmission electron microscopy at room temperature. Several common features are found. (1) The microscopic motion of dislocations is generally steady and continuous, suggesting that it is controlled by the Peierls mechanism. (2) Screw dislocations have the lowest mobility and undergo frequent cross-slip, especially for non-basal glide in wurtzite crystals; as a result, they become cusped as they advance and are eventually immobilized. (3) The mobility of the dislocations is not influenced by illumination from a light source introduced into the spevimen chamber of the microscope. A high density of stacking faults is produced on the (0001) plane by the motion ot'Shockley partials in ods and Odse, but not in ZnO. These results have been discussed in connection with the macroscopie plastic behaviour.