The asymmetric deformation of GaAs single crystals

The deformation of Si-doped GaAs single crystals with a carrier concentration of 1018 cm−3 was investigated by determining the stress/strain relationships for α and β bending at 500 °C. Marked differences were found between the α and β deformation curves. Using Gilman and Johnston’s model for dislocation multiplication and combining it with a linear relationship between the dislocation velocity and applied stress, a theoretical model was developed to explain the above-mentioned differences in terms of dislocation mobilities μ, dislocation multiplication factors C, activation stresses τa, and the initial densities of dislocation sources ρ0. Applying a numerical curve fitting procedure to the experimental curves, these parameters were found to have the following values for α and β bending, respectively: μα=8.5×10−12 and μβ=3.8×10−12 cm3 dyn−1 sec−1; Cα=89 and Cβ=130 cm−1; τaα=2.11×108 and τaβ=2.7×108 dyn cm−2; ρ0α=9×105 and ρ0β=4.5×102 cm−2.