Photoluminescence quenching in Si1−xGex/Si multiple quantum wells grown with atomic hydrogen

We compare the photoluminescence spectra from a series of Si1−xGex/Si (0.1⩽x⩽0.3) multiple quantum well (MQW) samples grown with atomic hydrogen to a series of similar samples grown without atomic hydrogen. All of the samples were grown at 710 °C. We observe intense quantum confined photoluminescence in the Si1−xGex/Si MQW samples grown without atomic hydrogen. No quantum confined photoluminescence was observed in the Si1−xGex/Si MQW samples grown with atomic hydrogen. This was unexpected, since quantum confined photoluminescence has been observed in the hydrogen-assisted growth of Si1−xGex/Si quantum well structures grown at lower temperatures by other researchers. We believe that this is caused by defects, introduced into the samples during growth with atomic hydrogen, which lead to efficient nonradiative centers that compete with the radiative centers. These defects lead to a reduction of the photoluminescence of the samples grown with atomic hydrogen. Since hydrogen is used as a surfactant to reduce the deleterious effects due to Ge segregation, understanding its role is an important step in SiGe materials development.