INTERNAL-FRICTION DUE TO KINK MOTION AND KINK PAIR FORMATION IN INTRINSIC AND N-DOPED GERMANIUM

Measurements of the internal friction on deformed Ge at frequencies from 0.2 to 20 Hz at temperatures between 150 and 820 K show two maxima α and β, occurring after deformation only. Their activation enthalpy H, prefactor f0, and relaxation strength Δ are: Hα = (1.108 ± 0.01) eV, f0α = (0.14 to 15) × 109 s-1 (increasing with increasing deformation), Δα 10-2; Hβ = (2.07 ± 0.2) eV, f0β 1013 s-1, Δβ 3 × 10-2. Both shift to lower temperatures with increasing deformation. They are attributed to the movement of geometrical kinks (α) and to kink pair formation (β) on single partial dislocations. Doping with (2 to 4) × 1017 cm-3 Sb lowers the kink migration enthalpy Hα by 0.3 to 0.4 eV. This indicates that the lowering of the activation enthalpy of the dislocation velocity by doping is due to that of the kink migration enthalpy Hα only.