Misfit dislocations at ErAs/GaAs heterojunctions

Misfit dislocations at the ErAs/GaAs interfaces grown by molecular-beam epitaxy have been investigated using the weak-beam technique of transmission electron microscopy (TEM). The observed dislocation configurations are significantly different from those at heterojunctions between “diamond-cubic” structured materials. Networks of nearly orthogonal dislocation, with dislocations lying approximately along [010] and [001] dislocations, and honeycomb-like dislocation networks have been observed. The dislocation density increases as the ErAs layer thickness increases. Different dislocation reactions between the a/2〈110〉 type dislocations, which result in complex dislocation configurations, are discussed. Slight misalignment of the epilayer with respect to the substrate is possible if there are uneven distributions of inclined Burgers vectors in different orientations or screw components in the dislocation network at the interface.