Investigations of the misfit dislocation structure at a CdTe(001)/ga As(001) interface using Stillinger-Weber potentials and high-resolution transmission electron microscopy

In this paper, Stillinger-Weber potentials which accurately describe the elastic constants of CdTe and GaAs are developed. These potentials are applied to investigate the misfit dislocation structure at a CdTe(001)/GaAs(001) interface. Based on these calculated structures, simulated high-resolution transmission electron microscopy images are compared with experimentally observed images. It will be shown that, although the exact energetics of the interface are not provided by these potentials, dislocation stand-off is more strongly influenced by the Poisson expansion or contraction of the individual materials. Further, the best agreement between the experimentally observed and simulated images is obtained when the dislocations occur at the interface with no stand-off being exhibited. The calculated structures indicate that the misfit dislocation structure exhibited along the [110] direction is different from that along the [110] direction if the initial monolayer of material, in this case believed to be tellurium, is misfitting with the substrate. This is brought about by the tetrahedral nature of the constituent materials and is not directly related to the zincblende structure.