It was noted that elemental dislocation mechanisms could be observed over large areas in low-misfit systems (m<1%). This provided information on the manner in which relaxation proceeded in higher-misfit hetero-epitaxial systems where large dislocation densities were rapidly generated and in which these mechanisms were not so easy to discern among the dislocation configurations which resulted from this highly deformed state. Hetero-epitaxial and homo-epitaxial systems in which nucleation and dislocation multiplication occurred were studied. The Matthews mechanism for misfit dislocation nucleation was observed in a very metastable situation. This was attributed to thermal activation of the source length rather than to reported processes. During the development of dislocations, several types of interaction occurred; leading to threading segments. The very frequent occurrence of cross-slip and multiple cross-slip events permitted relaxation to proceed in spite of blocking interactions. This unexpectedly easy cross-slip could be related to a shrinkage in the fault ribbon, close to the surface, due to image forces.

Low Misfit Systems as Tools for Understanding Dislocation Relaxation Mechanisms in Semiconducting Heteroepitaxial Films. B.Pichaud, N.Burle, M.Putero-Vuaroqueaux, C.Curtil: Journal of Physics - Condensed Matter, 2002, 14[48], 13255-67