Non-steady-state tunnelling recombination in insulating solids, controlled by defect diffusion and rotation

The experimental data for KCl-Ag, KBr, NaCl-Ag and KC1-SO₄ crystals as well as Na₂O3SiO₂-Tb³⁺ glass are summarized which demonstrate the delayed increase (decrease) of the intensity of the thermally stimulated tunnelling recombination of radiation defects after step-wise defrosting (frosting) of their mobility. Both theory and experiment presented here allow to distinguish the cases when the recombination kinetics is controlled by the rotation of an anisotropic defects or their diffusion respectively. It can be achieved studying the non-steady-state stages of kinetics. The effect of relative spatial defect distribution upon the kinetics under study is considered; it is argued that the {F, Vk} recombination in KBr occurs within spatially correlated pairs.