Nonpolar InGaN/GaN Core-Shell Single Nanowire Lasers.

Area of Science:

• Semiconductor Nanowire Lasers
• Quantum Well Engineering
• Optoelectronics

Background:

• Indium gallium nitride (InGaN) and gallium nitride (GaN) core-shell nanowires are promising for optoelectronic devices.
• Nonpolar crystal orientations are crucial for efficient light emission in InGaN/GaN systems.
• Achieving low-threshold lasing in nanoscale devices remains a significant challenge.

Purpose of the Study:

• To report lasing from nonpolar p-i-n InGaN/GaN multi-quantum well core-shell single-nanowire lasers.
• To investigate the performance of these nanowire lasers under optical pumping at room temperature.
• To explore the potential of this architecture for nanoscale light emitters.

Main Methods:

• Fabrication of nonpolar p-i-n InGaN/GaN core-shell nanowires using a hybrid top-down and bottom-up approach.
• Optical pumping to induce lasing.
• Micro-photoluminescence spectroscopy to measure modal gain spectra and gain curves.
• Hakki-Paoli method for gain analysis.
• Mode simulations to understand optical confinement.

Main Results:

• Successful demonstration of lasing in nonpolar InGaN/GaN core-shell nanowire lasers at room temperature.
• Significantly lower lasing thresholds compared to semipolar nanowires, attributed to high optical gain.
• Enhanced optical confinement in annular-shaped modes due to the core-shell architecture.
• Shorter cavity lengths and reduced active region volume achieved.

Conclusions:

• The p-i-n nonpolar core-shell nanowire architecture is viable for low-threshold, coherent UV-visible nanoscale light emitters.
• This work opens a route toward monolithic, integrable, electrically injected single-nanowire lasers.
• The findings pave the way for next-generation nanoscale optoelectronic devices.