Single-Mode Emission From Ge Quantum Dots in Photonic Crystal Nanobeam Cavity

A freestanding one-dimensional photonic crystal nanobeam cavity embedded with Ge self-assembled quantum dots is designed and fabricated on a silicon-on-insulator substrate. Only one photoluminescence peak is observed in the wavelength range of 1000 to 1600 nm at room temperature. The emission peak dominates the photoluminescence spectrum over an almost flat and weak background emission, which indicates single-mode emission is realized in the proposed light emitter.