Monolithically Integrated High-β Nanowire Lasers on Silicon

Area of Science:

• Optoelectronics
• Materials Science
• Nanotechnology

Background:

• Monolithic integration of lasers onto silicon is crucial for advanced optical interconnects.
• III-V semiconductor nanowires (NWs) offer potential for on-chip lasers due to their unique properties.
• Previous attempts at NW lasing on silicon were hindered by poor interface reflectivity.

Purpose of the Study:

• To demonstrate low-threshold, single-mode lasing in nanowire lasers integrated on silicon.
• To overcome the modal reflectivity limitations at the nanowire-silicon interface.
• To explore the potential for high-speed optical communication applications.

Main Methods:

• Fabrication of core-shell GaAs-AlGaAs nanowire lasers on silicon using epitaxial growth.
• Introduction of a tailored dielectric interlayer at the nanowire-silicon interface.
• Characterization of lasing performance, including threshold energy, spontaneous emission factor, and pulsation rates at low temperatures.

Main Results:

• Achieved low-threshold, single-mode lasing in vertical-cavity nanowire lasers on silicon.
• Measured a high spontaneous emission factor (β = 0.2), comparable to nanocavity lasers.
• Demonstrated ultralow threshold pump energies (≤11 pJ/pulse) and potential for high pulsation rates (≥250 GHz).

Conclusions:

• The dielectric interlayer effectively enhances modal reflectivity, enabling efficient nanowire lasing on silicon.
• These monolithic nanowire lasers exhibit high efficiency and speed, making them promising for chip-level optical interconnects.
• This work represents a significant step towards realizing integrated silicon photonics for high-performance computing and communication.