Transmission electron microscopy of (001) CdTe on (001) GaAs grown by metalorganic chemical vapor deposition

The nature of dislocations in (001) CdTe-(001) GaAs heterostructures was investigated by transmission electron microscopy. The samples were grown by metalorganic chemical vapor deposition with CdTe layer thicknesses h ranging from 0.1 to 2.2 μm. The interface contains an array of misfit dislocations spaced about 31 Å apart, independent of h. These dislocations do not relax all of the lattice mismatch (14.6%) in the CdTe layers with h<1 μm. Above the interfaces, surface nucleated dislocations are observed in the CdTe layers and their density depends on h. No evidence of an oxide or foreign interface layer was found in these samples.