MBE growth of InAs/GaAs quantum dot lasers on V-grooved (001) Si

The monolithic integration of InAs/GaAs quantum dot (QD) lasers on the silicon platform is critical for current high-speed optical communication and computing systems. However, the heteroepitaxial growth of high-performance InAs/GaAs QD lasers on complementary metal-oxide-semiconductor-compatible on-axis (001) Si substrates remains challenging due to the crystalline defects arising from substantial material dissimilarities. In this work, we present InAs/GaAs QD lasers grown entirely by molecular beam epitaxy (MBE) directly on pre-patterned V-grooved (001) Si substrates. Unlike previous approaches that combine MOCVD and MBE processes or employ homoepitaxial Si regrowth to form (111) facets, our method uses substrates with pre-defined (111) facet exposure, avoiding additional surface engineering. The combination of the V-grooved geometry of the substrate and the stepped growth method enables antiphase boundary-free GaAs buffer growth. Further optimisation of InAlAs/GaAs dislocation filtering layers and QD growth parameters yielded a threading dislocation density of 2.91 × 10 7 cm -2 and room-temperature emission around 1.3 μm was achieved. With the improved buffer, O-band lasing up to 90 °C has been demonstrated for InAs/GaAs QD lasers. This structure offers a simplified and thermally robust route for monolithic QD laser integration, potentially supporting scalable silicon photonic platforms.