ON THE IMPROVEMENT IN THERMAL QUENCHING OF LUMINESCENCE IN SIGE SI STRUCTURES GROWN BY MOLECULAR-BEAM EPITAXY/

Thermal quenching of photoluminescence (PL) from SiGe/Si quantum well (QW) structures grown by molecular beam epitaxy is shown to be more se vere when grown at a lower temperature. The mechanism responsible for the thermal quenching of PL is discussed as being due to thermally act ivated nonradiative recombination channels, related to defects in both Si barriers and SiGe QW. Nonradiative defects in Si can be rather eff iciently deactivated by post-growth treatments such as hydrogenation a nd thermal annealing, leading to a significant improvement in the ther mal quenching behavior of PL from single QW structures. Nonradiative d efects in SiGe are found to be thermally stable, on the other hand, ev ident from the experimentally observed minor role played by post-growt h thermal annealing in the thermal quenching of PL from multiple QW st ructures. (C) 1998 American Vacuum Society.