Local trapping and recombination of charge carriers in heterostructures with Ge nanoclusters

Abstract

To investigate the recombination processes, we study the spectral and time dependences of lateral photoconductivity of Si/Ge heterostructures with SiGe nanoclusters, obtained by molecular beam epitaxy. Photoconductivity at low temperatures, in the spectral region where Si is transparent, is conditioned by transitions involving localized states of SiGe nanoclusters. When the temperature decreases the most significant decrease in the photoconductivity is due to fundamental absorption in nanoclusters. This shows the high efficiency of electron–hole recombination centers in SiGe nanoclusters.