Breakdown of donor localized states on the insulating side of strain-induced MI transitions in Si and Ge

Localization of electrons on hydrogenic impurity atoms in Si and Ge and the ir delocalization by electric field breakdown of the localized states were examined on the insulating side of a strain-induced metal-nonmetal transiti on. Both nonlinear and linear dependencies of the breakdown field on activa tion energy were obtained. Experimental results were explained taking into account a crucial transformation of silicon and germanium conduction band s tructure under extremely high uniaxial pressure.