Room temperature continuous-wave green lasing from an InGaN microdisk on silicon

Area of Science:

• Semiconductor Optoelectronics
• Materials Science
• Nanotechnology

Background:

• Indium Gallium Nitride (InGaN) based materials are crucial for optoelectronic devices.
• Achieving low-threshold lasing in micro-disk resonators is essential for efficient light emission.
• Integration of nitride-based devices on silicon substrates presents significant fabrication challenges.

Purpose of the Study:

• To demonstrate optically pumped green lasing with an ultra-low threshold.
• To develop a cost-effective fabrication process for InGaN/GaN micro-disks on silicon.
• To investigate the lasing characteristics and underlying recombination dynamics.

Main Methods:

• Fabrication of InGaN/GaN micro-disks (approx. 1 μm diameter) using a silica micro-sphere approach, dry-etching, and chemical etching.
• Optical pumping using a continuous-wave laser diode at room temperature.
• Characterization via time-resolved micro photoluminescence (PL) and confocal PL measurements.

Main Results:

• Achieved optically pumped green lasing with an ultra-low threshold of 1 kW/cm².
• Fabrication process resulted in minimized sidewall roughness and excellent circular geometry.
• Confirmed lasing action in whispering gallery modes and analyzed excitonic recombination dynamics.

Conclusions:

• The developed fabrication technique enables efficient InGaN/GaN micro-disk lasers on silicon.
• The ultra-low lasing threshold demonstrates the potential for high-performance photonic devices.
• The study provides insights into the excitonic behavior governing the lasing performance.