Dislocation Mobility in Germanium

The stress and temperature dependence of the glide velocity of individual dislocations in pure germanium has been measured by means of an etch-pit technique. The motion may be described by a thermal activation energy which, for 60° dislocations, varies from 1.49 eV at 8.0 kg/${\mathrm{mm}}^2$ to 2.25 eV at 0.8 kg/${\mathrm{mm}}^2$. For screws, it is 1.47 eV independent of stress. At constant temperature, the velocity varies with stress in a complex manner which is not adequately accounted for by previous theories alone.