An investigation was made of non-radiative defects in Si epilayers and in SiGe/Si heterostructures which had been grown by means of molecular beam epitaxy. Several non-radiative defects were observed by applying the optically detected magnetic resonance technique to samples with various structures. These defects could be introduced into the materials, at low growth temperatures, as a result of a low surface adatom mobility. They could also be introduced by exposure to accelerated positive ions under non-optimized conditions during growth. These defects provided efficient non-radiative channels for carrier recombination, and could be partially deactivated by post-growth H treatments.

W.M.Chen, I.A.Buyanova, A.Henry, W.X.Ni, G.V.Hansson, B.Monemar: Materials Science Forum, 1995, 196-201, 473-8