Important nonradiative grown-in defects in MBE-grown Si and SiGe/Si heterostructures

We report on our recent results from investigation of nonradiative defects in Si epilayers and SiGe/Si heterostructures grown by molecular beam epitaxy (MBE). Several nonradiative defects are observed, by the optical detection of magnetic resonance (ODMR) technique, in samples of various structures and growth conditions. These defects can be introduced in the materials as a result of a low surface adatom mobility at a low growth temperature and, more severely, by exposure to accelerated positive ions under non-optimised conditions during the growth. These defects provide efficient non-radiative channels for carrier recombination and can be partially deactivate try post-growth hydrogen treatment.