Z-contrast imaging of dislocation cores at the GaAs/Si interface

The interface between silicon and epitaxial GaAs thin film grown by metalorganic chemical vapor deposition was studied using atomic-resolution Z-contrast imaging. Z-contrast imaging provides chemical composition information and allows direct interpretation of micrographs without simulation. Three different types of dislocations were identified. As expected, a dangling bond was found in the atomic structure of the 60degrees dislocation. One of the observed 90degrees dislocations had the reconstructed atomic core structure (with no dangling bonds). The core structure of the other 90degrees dislocation exhibited a dangling bond. (C) 2002 American Institute of Physics.