InGaAs/GaAs nano-ridge laser with an amorphous silicon grating monolithically grown on a 300 mm Si wafer

The monolithic growth of direct-bandgap III-V materials directly on a Si substrate is a promising approach for the fabrication of complex silicon photonic integrated circuits including light sources and amplifiers. It remains challenging to realize practical, reliable, and efficient light emitters due to misfit defect formation during the epitaxial growth. Exploiting nano-ridge engineering (NRE), III-V nano-ridges with high crystal quality were achieved based on aspect ratio defect trapping inside narrow trenches. In an earlier work, we used an etched grating to create distributed feedback lasers from these nano-ridges. Here we deposited an amorphous silicon grating on the top of the nano-ridge. Under pulsed optical pumping, a ∼7.84 kW/cm² lasing threshold was observed, ∼5 times smaller compared to devices with an etched grating inside the nano-ridge. Compared to the etched grating, the amorphous silicon grating introduces no extra carrier loss channels through surface state defects, which is believed to be the origin of the lower threshold. This low threshold again demonstrates the high quality of the epitaxial deposited material and may provide a route toward further optimizing the electrically driven devices.