Dynamics of dislocations in InSb and GaAs crystals

Abstract

An asymmetry of the mobility of 60° α and screw dislocations in nominally pure InSb and GaAs single crystals has been studied as a function of shear stress (τ ≈ 1–50MPa) and temperature (T ≈ 323–773 K). The observed synchronous decrease in the mean free path length and the mean number of mobile dislocations under periodic tensile-compressive and monotonic multiple-tension loadings are most clearly manifested for dislocations prone to a noticeable cross-slip (screws containing β partials). It has been found that variations in the dislocation stacking fault width with increasing shear stress τ under compression and extension affect the dislocation velocity in InSb and GaAs in different manners. An estimation of the Peierls stress τ_P shows that τ_P≤10 −6μ (μ is the shear modulus) in A³B⁵ covalent compounds, whereas τ_P≤10⁻⁵μ in the elemental semiconductors Si and Ge. The data on acoustoplastic, electroplastic and photoplastic effects in semiconductors may be unambiguously explained using a universal model for the motion, drag and multiplication of dislocations by means of non-conservative and conservative motion of jogs and conservative kink pairs produced by stress-aided double cross-slip and climb of dislocations as proposed by Kisel in 1976.