Optical pumped InGaAs/GaAs nano-ridge laser epitaxially grown on a standard 300-mm Si wafer

Abstract

Fully exploiting the potential of silicon photonics requires high-performance active devices such as lasers, which can be monolithically integrated in a scalable way. However, direct bandgap III–V semiconductors exhibit a large lattice mismatch and/or strongly differing thermal expansion coefficient with silicon. This makes monolithic integration on silicon without introducing excessive defects in the material extremely difficult. The majority of the methods proposed thus far either are not compatible with further low-cost integration or rely on a special substrate. Here we demonstrate monolithic InGaAs/GaAs single-mode nano-ridge lasers directly grown on a standard (001) 300-mm Si wafer. Exploiting the aspect ratio defect trapping technique, unwanted defects are confined to a narrow trench defined in the silicon substrate. The nano-ridge structures subsequently grown out of these trenches are of high crystalline quality as shown by high-resolution transmission electron microscopy analysis and a strong photoluminescence response. They can be controlled in shape by optimizing the growth conditions, which allows us to minimize substrate leakage and maximize confinement in the InGaAs quantum wells providing optical gain. Distributed feedback lasers were fabricated by defining a first-order grating in the nano-ridge. Under pulsed optical pumping, single-mode lasing with side mode suppression over 28 dB was shown, and precise control of the emission wavelength over 60 nm was achieved. This demonstration proves the high quality of the material and provides a credible road towards a CMOS-compatible platform for high-volume manufacturing of silicon photonic integrated circuits, including laser and amplifier devices.