Room temperature direct gap electroluminescence from Ge/Si0.15Ge0.85 multiple quantum well waveguide

We report room temperature direct gap electroluminescence (EL) from a Ge/Si0.15Ge0.85 multiple quantum well (MQW) waveguide. The excitonic direct gap transition and the dependence of the EL intensity on the injection currents and temperature are clearly observed. EL from the Ge/SiGe MQWs is shown to have a transverse-electric polarization. These results demonstrate the strong potential of the Ge/Si0.15Ge0.85 MQWs in terms of the realization of a monolithically integrated light source on the Si platform.