Dislocations in vapor-grown compositionally graded (In,Ga)P

Dislocation morphologies in compositionally graded vapor-phase epitaxial (VPE) layers of (In,Ga)P deposited on (100) GaP substrates have been determined via transmission electron microscopy using (011) cross-sectional samples. Evidence for the introduction of misfit dislocations by slip and from substrate dislocations has been found. These processes lead to the familiar crossed array of dislocations at an interfacial misfit plane. Evidence for Frank-Read sources, which are pinned dislocation segments in the crossed array, and dislocation annihilation is also presented. Asymmetric arrays of dislocations at compositional steps have been observed.