Direct observation of intrinsic core structure of a partial dislocation in ZnS

Mobility of dislocations in compound semiconductor materials can be changed by light illumination because the core structure of dislocations is supposed to be reconstructed by photoexcited carriers. However, the atomic structure of such dislocation cores has not been observed and is still poorly understood. In this study, we introduced dislocations in ZnS, one of the typical II–VI type compound semiconductors, by deformation under darkness, and investigated the atomic structure of the dislocation cores using scanning transmission electron microscopy (STEM) combined with theoretical calculations. Direct observation of the Zn core partial dislocation revealed that its atomic structure is in good agreement with the theoretically predicted dislocation core without electron trapping. Moreover, the dislocations were observed to move along a slip plane during the observation. These results indicate that the electron-trap-free dislocation is mobile and could be the origin of plasticity in the dark.