Effect of irradiation on the luminescence properties of low-dimensional SiGe/Si(001) heterostructures

This study is concerned with the effect of irradiation on the luminescence properties of low-dimensional Si/Ge heterostructures with different degrees of spatial localization of charge carriers. It is shown that the radiation stability of Si/Ge heterostructures is improved with increasing efficiency of localization of charge carriers in the structures. The spatial localization of charge carriers in the SiGe nanostructures decreases the probability of nonradiative recombination of charge carriers at radiation defects produced in the Si matrix. It is demonstrated that, among the structures explored in the study, the highest radiation stability of luminescence properties is inherent in the multilayered structures containing self-assembled Ge(Si) nanoislands, in which the most efficient spatial localization of charge carriers is attained. In this case, the localization is three- and two-dimensional, correspondingly, for holes in the islands and for electrons in the Si layers that separate neighboring layers containing the islands.