Important defect aspects in optoelectronic applications of Si- and SiGe/Si-heterostructures

We have carried out a systematic investigation of non-radiative defects in Si-epilayers and SiGe/Si-heterostructures grown by molecular beam epitaxy (MBE). A number of non-radiative defects are observed, by the optically detected magnetic resonance (ODMR) technique, and are shown to depend critically on the sample structures and growth conditions. Experimental evidence on the mechanisms for the introduction of these defects are provided. These defects provide efficient non-radiative channels for carrier recombination and, to a large extent, control the carrier lifetime.