Recombination-enhanced dislocation motion in SiGe and Ge

In-situ straining experiments on dislocation motion in Ge and Si-5 at% Ge a lloy single crystals are performed in a high voltage transmission electron microscope. In comparison with previous results by other methods, the dislo cation velocities are found to be enhanced due to a recombination enhanceme nt owing to the excess carrier injection by the electron beam. The reductio n in the activation energy of dislocation motion is ascribed to the recombi nation-assisted kink formation. The kink migration energy is estimated to b e 0.7 eV in Ge and 1.5 eV in SiGe.