On-Chip Monolithically Integrated Ultraviolet Low-Threshold Plasmonic Metal-Semiconductor Heterojunction Nanolasers

Area of Science:

• Optoelectronics
• Materials Science
• Nanotechnology

Background:

• Metal-semiconductor heterojunctions are crucial for electrically driven nanolasers but face fabrication challenges and limitations with noble metals.
• Existing plasmonic nanolasers often require high thresholds, cryogenic temperatures, or substrate removal, hindering monolithic integration.
• Current methods struggle with ohmic loss and low modal reflectivity, preventing scalable microelectronic manufacturing.

Purpose of the Study:

• To demonstrate record-low-threshold, room-temperature ultraviolet (UV) lasing from plasmon-coupled core-shell nanowires directly grown on silicon.
• To overcome the fabrication complexity and material incompatibility issues hindering previous nanolaser development.
• To enable monolithic fabrication of UV nanolasers compatible with silicon microelectronics.

Main Methods:

• Direct growth of core-shell metal-semiconductor nanowires on silicon substrates.
• Utilizing the naturally formed heterostructure to enhance nanowire growth density and plasmonic resonance.
• Coupling intense plasmonic resonance with a resonant Fabry-Pérot microcavity.

Main Results:

• Achieved a 100-fold improvement in nanowire growth density compared to previous studies.
• Demonstrated room-temperature UV lasing in the 340-360 nm range with a record-low threshold of 12 kW cm⁻².
• Observed a significant boost in emission strength (factor of 100) and a high spontaneous emission coupling factor (≈0.32).

Conclusions:

• The developed hybrid photonic-plasmonic system offers a simple, cost-competitive architecture for future UV sources.
• Direct silicon integration of plasmon-coupled core-shell nanowires overcomes limitations of previous nanolaser technologies.
• This approach facilitates the realization of chip-level UV optoelectronic devices for diverse applications.