Single crystals of highly Zn-doped material were compressed along <123> during constant strain-rate tests at temperatures of between 330 and 700C. The yield point was studied in both the as-grown and pre-deformed states, by means of strain-rate and temperature-change tests. Two deformation regimes were detected in as-grown material. At low temperatures, the deformation was governed by the kink mechanism which was typical of tetrahedrally coordinated semiconductors. The activation energy and the stress exponent were deduced to be 1.44eV and 3.0. These values were similar to those obtained for undoped GaAs; thus indicating that Zn additions did not appreciably influence the activation energies of kink formation and migration. Nevertheless, a marked efficiency of Zn in locking dislocations was observed. At higher temperatures, a different regime appeared which was also observed in other highly-doped semiconductors. The basic mechanism in this regime was unknown. Material which was pre-deformed in temperature-change tests exhibited characteristic deviations. In these experiments, the crystals behaved as if the point-defect concentrations or locking efficiency of obstacles had been appreciably increased during pre-deformation.

Yield point of as-grown and pre-deformed GaAs:Zn H.G.Brion, H.Siethoff: Journal of Applied Physics, 1998, 84[9], 4885-90