Strong Room-Temperature Electroluminescence from Ge-on-Si by Precise in-situ Doping Control

We observe strong room-temperature electroluminescence from Ge-on-Si. Ge p-i-n junction is formed within the epitaxial Ge by the precise in-situ doping method and additionally high density P delta doping is performed in the vicinity of the surface to create a low resistivity Ohmic contact. An EL device was mesa-defined by the photo-lithography and following reactive ion etching process in order to suppress leak current. Current-voltage characteristic reveal a good diode rectifying property with an on/off ratio of over 105. The EL spectrum appears at around 2.1 kA/cm2 injected current, and the EL intensity drastically increases with the injection current increase. These results indicate that the Ge-on-Si p-i-n structure has high potential to realize high efficiency Ge lasers monolithically integrated on the Si platform.