Continuous-wave InAs/GaAs quantum-dot laser diodes monolithically grown on Si substrate with low threshold current...

Area of Science:

• Semiconductor Physics
• Materials Science
• Optoelectronics

Background:

• Monolithic integration of III-V quantum-dot (QD) lasers on silicon (Si) substrates is crucial for advanced photonic integrated circuits.
• Previous efforts faced challenges in achieving efficient and stable room-temperature operation of such devices.

Purpose of the Study:

• To demonstrate the first room-temperature continuous-wave (CW) operation of III-V quantum-dot laser diodes monolithically grown on a Si substrate.
• To achieve low threshold current densities for silicon-based lasers.

Main Methods:

• Fabrication of long-wavelength Indium Arsenide/Gallium Arsenide (InAs/GaAs) quantum-dot structures on Germanium-on-Silicon (Ge-on-Si) substrates.
• Utilizing ridge-waveguide laser structures with as-cleaved facets.
• Characterization of lasing performance under continuous-wave (CW) and pulsed conditions at room temperature.

Main Results:

• Successful room-temperature CW lasing at a wavelength of 1.28 μm was achieved.
• Threshold current densities of 163 A/cm² (CW) and 64.3 A/cm² (pulsed) were recorded.
• The pulsed threshold current density of 64.3 A/cm² is the lowest reported for any type of laser on Si at room temperature.

Conclusions:

• The study demonstrates the feasibility of monolithically integrating high-performance III-V quantum-dot lasers onto Si substrates.
• This achievement paves the way for cost-effective and scalable silicon photonics.
• The low threshold current density signifies a significant advancement in silicon-based laser technology.