A Defect-Free Vertical-Cavity GaAs-Based Nanowire Laser on Silicon Emitting at the Telecom O-Band

Telecom-band vertical-cavity nanowire (NW) lasers are promising integrated light sources for silicon (Si) photonics applications but have remained elusive within the important GaAs materials system. Here, we demonstrate the direct site-selective integration of a vertical-cavity GaAs-based NW laser on Si that exhibits lasing emission in its as-grown geometry at the telecom O-band (∼1.3 μm). This achievement relies on an advanced NW heterostructure using an InGaAs/InAlGaAs multiple quantum well (MQW) active gain region coaxially integrated on a vertical GaAsSb NW core with high Sb content to minimize strain energy. Consequently, uniform composition throughout the entire MQW and minimal strain (<1.3 ± 0.2%) with no extended defects are verified by scanning transmission electron microscopy and nanobeam electron diffraction. Single-mode lasing is consistently observed for a range of operation temperatures under optical pumping with lasing thresholds as low as 160 μJ/cm². Mode-dependent threshold gain analyses reveal further that a high-order transverse mode is responsible for lasing.