Atomic structure, stability, and dissociation of dislocations in cadmium telluride

Abstract

Dislocation plays a crucial role in many material properties of semiconductors, ranging from plastic deformation to electronic transport. But the dislocation structures and reactions remain controversial in many semiconductors. Here, we systematically examine the dislocation properties of cadmium telluride (CdTe), a prototype of II-VI compound semiconductors, using molecular statics and molecular dynamics simulations with a machine-learning force field. We find that dislocation cores in CdTe are not reconstructed along the dislocation line due to the significant ionic bonding characteristics. Moreover, the undissociated screw dislocation in the shuffle set is more stable than that in the glide set, and the glide dislocation tends to move to the shuffle set, followed by random movement rather than dissociation, arising from its low Peierls stress. For 60° perfect dislocation, it also prefers to locate in the shuffle set, but the 60° glide dislocation is dissociated into a pair of 30° and 90° partial dislocations connected by a stacking fault with a width of ∼9.03 nm at low temperatures through reconfiguring atomic bonds in the core. This work provides an atomic-level understanding of dislocation core properties in CdTe, laying a basis for interpreting the mechanical and electronic performance of CdTe and other II-VI semiconductors.