Direct observation of stacking fault nucleation in the early stage of ZnSe/GaAs pseudomorphic epitaxial layer growth

The nucleation of stacking faults in the initial stage of growth of ZnSe/GaAs(001) epilayers has been studied by high-resolution transmission electron microscopy. Stacking faults have been observed to nucleate on the {111} planes on the slopes of ZnSe islands and hang over the adjacent (001) surface. The image details of a V-shaped fault originating from a sharp tip at a later stage of growth is in good agreement with the simulated image of stacking faults emerging from a dimer array of three chains. This gives support to residual dimer array on the 2×1 reconstructed (001) surface as the origin of stacking faults in ZnSe epilayers.