Enhancement of room temperature electroluminescence from strained SiGe/Ge(111) multiple quantum wells light emitting diodes

Epitaxially grown Ge-on-Si(111) based vertical type light-emitting diodes (LEDs) including a single strained SiGe layer or strained SiGe/Ge multiple quantum wells (MQWs) as intrinsic active layers are fabricated and their electroluminescence (EL) properties are compared. It is found from their diode characteristics that off-leakage currents are highly suppressed by the strained SiGe insertion, and resultantly, markedly enhanced room-temperature EL emission is obtained for the SiGe/Ge MQWs LED compared to LED with only Ge active layer, indicating that the strained SiGe/Ge heterostructures are promising toward high efficiency light source in the Si photonics.