Electroluminescence from the Ge quantum dot MOS tunneling diodes

A Ge quantum dot (QD) light-emitting diode (LED) is demonstrated using a MOS tunneling structure for the first time. The oxide film was grown by liquid phase deposition at 50/spl deg/C to reduce the thermal budget. The infrared emission of /spl sim/1.5 /spl mu/m was observed from Ge QD MOS LEDs, similar to the p-type-intrinsic-n-type structure reported previously. At the negative gate bias, the electrons in the Al gate electrode tunnel to the Ge QD through the ultrathin oxide and recombine radiatively with holes to emit the /spl sim/1.5/spl mu/m infrared. The electrons also recombine with holes in the Si cap, and the band edge emission from Si is also observed.