Dislocations in deformed Ge1-xSix alloys, where x ranged from 0 to 1, were investigated by means of weak-beam transmission electron microscopy. They were dissociated into Shockley partial dislocations which bounded intrinsic stacking-faults. It was found that the intrinsic stacking-fault energy decreased from 61 to 55mJ/m2, with increasing Si content (table 10). This decrease in stacking-fault energy with increasing Si content was in agreement with previously reported data for this system. The stacking-fault energies of the alloys were intermediate between those of Ge and Si, and it was concluded that the stacking-fault energies obeyed Vegard's law with respect to composition. The fact that a large dissociation of dislocations, and an associated reduction in the stacking-fault energy, was not observed in the alloys suggested that there was no solute segregation around the dislocations; at least not during deformation. The present findings implied that the dynamic development of a solute atmosphere around dislocations might not be at the origin of alloy hardening.

Dislocation Dissociation and Stacking-Fault Energies in Ge1-xSix Alloys I.Yonenaga, S.H.Lim, D.Shindo: Philosophical Magazine Letters, 2000, 80[4], 193-7

Table 10

Dislocation Dissociation Widths and Stacking-Fault Energies for Ge1-xSix Alloys