Room-temperature photonic crystal nanocavity light emitting diodes based on Ge self-assembled quantum dots

Current-injected light emitting diodes (LEDs) based on Ge self-assembled quantum dots embedded in photonic crystal (PhC) nanocavities are demonstrated by using a lateral PIN diode. Strong resonant electroluminescence (EL) is obtained at room-temperature when the injected current is larger than 50 μA. Sharp resonant peaks corresponding to the PhC cavity modes, with Q-factor larger than 800, are observed in the EL spectrum. The current dependence of the light emission properties is also discussed. By collecting the light emission through a single-mode fiber, we measure the output power of the LED to be about 6 pW under 3 mA injected current.