Strain induced electronic alterations of dislocation mobility GeSi layers

The stress in strained GexSi1-x layers reduces, according to Hull et al. [A ppl. Phys. Lett. 65, 327 (1994)] the activation energy for dislocation glid e with increasing x. We explain this observation with the Fermi-level shift due to strain-induced band gap narrowing. We start from Jones' approach [P hil. Mag. B 42, 213 (1980)] to the effect of doping on dislocation mobility and consider the influence of the Fermi-level shift on the charge of kinks and thus the activation energy for dislocation glide. Using this model we can calculate the strain induced activation energy reduction without the ne cessity to use a fitting parameter.