INVESTIGATIONS OF THE MISFIT DISLOCATION-STRUCTURE AT A CDTE(001) GAAS(001) INTERFACE USING STILLINGER-WEBER POTENTIALS AND HIGH-RESOLUTIONTRANSMISSION ELECTRON-MICROSCOPY/

In this paper, Stillinger-Weber potentials which accurately describe t he 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, simula ted high-resolution transmission electron microscopy images are compar ed with experimentally observed images. It will be shown that, althoug h the exact energetics of the interface are not provided by these pote ntials, dislocation stand-off is more strongly influenced by the Poiss on expansion or contraction of the individual materials. Further, the best agreement between the experimentally observed and simulated image s is obtained when the dislocations occur at the interface with no sta nd-off being exhibited. The calculated structures indicate that the mi sfit dislocation structure exhibited along the [110] direction is diff erent from that along the [1(1) over bar0$] direction if the initial m onolayer of material, in this case believed to be tellurium, is misfit ting with the substrate. This is brought about by the tetrahedral natu re of the constituent materials and is not directly related to the zin cblende structure.