Silicon-Based Light-Emitting Devices Based on Ge Self-Assembled Quantum Dots Embedded in Optical Cavities

Highly efficient light-emitting devices operating in 1.3-1.6 μm wavelength range are realized by combining optical cavities and Ge self-assembled quantum dots (QDs) grown on SOI wafers by molecular beam epitaxy (MBE). Different types of optical cavities, including photonic crystal (PhC) nanocavities, microdisks, and microrings, are fabricated to enhance the light emission efficiency at room temperature. Sharp resonant peaks with Q-factor on the order of 10³ are observed in the micro-photoluminescence (μPL) spectrum. Through numerical simulation, these peaks are well identified as the corresponding cavity modes. The emission performances of these devices are also investigated by performing pumping-power- and geometric-parameter-dependent μPL measurements. The resonant wavelength, Q-factor, and emission intensity can be easily manipulated by these parameters.