The plasticity of GaAs between 415 and 730°C

GaAs single crystals grown by the liquid-encapsulated Czochralski method are compressed along ‘123’ under a protective atmosphere of flowing Ar. The resulting stress-strain curves, which are rather similar to those observed in other III-V compounds, are analysed according to the beginning of plastic deformation and to dynamical recovery. The lower yield point is characterized by an activation energy of l·24eV and a stress exponent of 3·5. Both values compare favourably with those obtained from measurements of the dislocation velocity. From the strain-rate and temperature dependence of the stress τIII at the onset of the first recovery stage, an activation energy of approximately 2eV is derived, which may be regarded as a lower bound for the activation energy of self-diffusion of the slowest-moving species. Comparing these results with those obtained for other semiconductors corroborates a view increasingly supported in the literature, namely that moving dislocations emit or absorb point effects.