Dislocation Velocities and Mechanical Strength of Bulk GeSi Crystals

The dislocation velocities and mechanical strength of bulk crystals of Ge1ÿxSix alloys have been investigated by the etch pit technique and compressive deformation tests, respectively. The velocity of dislocations has been determined as a function of stress and temperature in the composition ranges 0 < x < 0:08 and 0:94 < x < 1. In the composition range 0 < x < 1 the yield stress showed a maximum around x ˆ 0:5 and was dependent on the composition as being proportional to x…1ÿ x†. Built-in long-range internal stress fields in GeSi alloy caused by local fluctuations of the alloy composition together with dynamic development of the solute atmosphere around dislocations were thought to result in the strengthening of GeSi as a unique alloying effect.